diff --git a/docs/design/feature/realtime_ar_diffusion.md b/docs/design/feature/realtime_ar_diffusion.md
index 5963befe7f6..426ee5afd73 100644
--- a/docs/design/feature/realtime_ar_diffusion.md
+++ b/docs/design/feature/realtime_ar_diffusion.md
@@ -178,6 +178,24 @@ For LingBot World v2:
 - `lingbot_world/pipeline.py` constructs conditioning, owns small non-KV session state, and
   produces one block plus the standard metadata envelope.
 
+## Ulysses sequence parallelism
+
+LingBot supports pure Ulysses sequence parallelism for both direct and
+AR-Diffusion execution. With Ulysses degree greater than one, hidden tokens,
+camera features, token-expanded timestep modulation, and RoPE tables are sharded
+together. Without SP, timestep modulation retains the frame-broadcast path.
+Self-attention performs the sequence-to-head all-to-all before reading or writing
+paged KV, while static text K/V uses the same local head shard. Text K/V shards
+own compact storage; cross-attention exchanges query/output layouts to use these
+shards. This retains the shared cache geometry and reduces text K/V storage at
+the cost of two all-to-all calls per layer.
+
+The output head projects local tokens before gathering the flow values. For
+the 14B model this reduces the gathered width from 5120 to 64; frame modulation
+uses each shard's global token offset, including shards that split a frame. Only
+`ulysses_mode="strict"` is supported; `advanced_uaa`, Ring, and AllGather-KV modes
+remain unsupported for this model.
+
 ## Non-goals
 
 This contract does not currently provide:
diff --git a/examples/offline_inference/diffusion/lingbot_world_v2.py b/examples/offline_inference/diffusion/lingbot_world_v2.py
index 590442c4d84..4bbea2f4f69 100644
--- a/examples/offline_inference/diffusion/lingbot_world_v2.py
+++ b/examples/offline_inference/diffusion/lingbot_world_v2.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 """Generate a LingBot-World v2 video from an image and camera trajectory.
 
 The official checkpoint is licensed separately under CC BY-NC-SA and is
@@ -99,6 +99,7 @@ def parse_args(argv: Sequence[str] | None = None) -> argparse.Namespace:
         default=1,
         help="Number of GPUs used for tensor parallelism inside the DiT.",
     )
+    parser.add_argument("--ulysses-degree", type=int, default=1, help="Pure Ulysses sequence parallel degree.")
     parser.add_argument("--flow-shift", type=float, default=5.0, help="Positive FlowUniPC scheduler shift.")
     parser.add_argument("--fps", type=int, default=16, help="Frames per second in the exported MP4.")
     parser.add_argument("--output", default="lingbot_world_v2.mp4", help="Output MP4 path.")
@@ -158,6 +159,8 @@ def build_omni_kwargs(
 
     if args.tensor_parallel_size <= 0:
         raise ValueError("--tensor-parallel-size must be a positive integer.")
+    if args.ulysses_degree <= 0:
+        raise ValueError("--ulysses-degree must be a positive integer.")
     flow_shift = _positive_finite(args.flow_shift, "--flow-shift")
     model_path = Path(args.model).expanduser()
     model = str(model_path.resolve()) if model_path.exists() else args.model
@@ -165,6 +168,7 @@ def build_omni_kwargs(
         "model": model,
         "flow_shift": flow_shift,
         "tensor_parallel_size": args.tensor_parallel_size,
+        "ulysses_degree": args.ulysses_degree,
         "enforce_eager": args.enforce_eager,
         "model_config": {"lingbot_action_root": str(paths.action_root)},
     }
diff --git a/tests/diffusion/models/lingbot_world/test_lingbot_world_attention.py b/tests/diffusion/models/lingbot_world/test_lingbot_world_attention.py
index f5567a706d1..3d883414e1e 100644
--- a/tests/diffusion/models/lingbot_world/test_lingbot_world_attention.py
+++ b/tests/diffusion/models/lingbot_world/test_lingbot_world_attention.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 
 from __future__ import annotations
 
@@ -7,7 +7,7 @@
 import math
 import sys
 from pathlib import Path
-from types import ModuleType
+from types import ModuleType, SimpleNamespace
 
 import pytest
 import torch
@@ -33,6 +33,10 @@
     "vllm_omni.diffusion",
     "vllm_omni.diffusion.attention",
     "vllm_omni.diffusion.attention.layer",
+    "vllm_omni.diffusion.distributed",
+    "vllm_omni.diffusion.distributed.comm",
+    "vllm_omni.diffusion.distributed.parallel_state",
+    "vllm_omni.diffusion.distributed.sp_plan",
     "vllm_omni.diffusion.layers",
     "vllm_omni.diffusion.layers.norm",
     "vllm_omni.diffusion.layers.rope",
@@ -58,6 +62,47 @@ def _install_vllm_stubs() -> None:
     distributed.get_tensor_model_parallel_world_size = lambda: 1
     distributed.tensor_model_parallel_all_reduce = lambda value: value
 
+    class _SeqAllToAll4D:
+        @staticmethod
+        def apply(group, value, scatter_idx, gather_idx, use_sync=False):
+            del group, scatter_idx, gather_idx, use_sync
+            return value
+
+    setattr(
+        sys.modules["vllm_omni.diffusion.distributed.comm"],
+        "SeqAllToAll4D",
+        _SeqAllToAll4D,
+    )
+
+    def get_sp_group():
+        return SimpleNamespace(
+            ulysses_world_size=1,
+            ulysses_rank=0,
+            ulysses_group=None,
+        )
+
+    setattr(
+        sys.modules["vllm_omni.diffusion.distributed.parallel_state"],
+        "get_sp_group",
+        get_sp_group,
+    )
+
+    class _SequenceParallelInput:
+        def __init__(self, split_dim, expected_dims=None, split_output=False, auto_pad=False):
+            self.split_dim = split_dim
+            self.expected_dims = expected_dims
+            self.split_output = split_output
+            self.auto_pad = auto_pad
+
+    class _SequenceParallelOutput:
+        def __init__(self, gather_dim, expected_dims=None):
+            self.gather_dim = gather_dim
+            self.expected_dims = expected_dims
+
+    sp_plan = sys.modules["vllm_omni.diffusion.distributed.sp_plan"]
+    setattr(sp_plan, "SequenceParallelInput", _SequenceParallelInput)
+    setattr(sp_plan, "SequenceParallelOutput", _SequenceParallelOutput)
+
     def set_weight_attrs(weight: torch.Tensor, attrs: dict) -> None:
         for name, value in attrs.items():
             setattr(weight, name, value)
@@ -541,3 +586,38 @@ def test_tp_rmsnorm_weight_loader_selects_rank_shard(monkeypatch: pytest.MonkeyP
     norm.weight.weight_loader(norm.weight, torch.tensor([10.0, 20.0, 30.0, 40.0]))
 
     torch.testing.assert_close(norm.weight, torch.tensor([30.0, 40.0]))
+
+
+def test_single_token_text_kv_shard_owns_compact_storage(monkeypatch):
+    module = _load_module()
+    monkeypatch.setattr(
+        module,
+        "get_sp_group",
+        lambda: SimpleNamespace(
+            ulysses_world_size=2,
+            ulysses_rank=1,
+            ulysses_group=None,
+        ),
+    )
+    attention = module.LingBotCrossAttention(dim=8, num_heads=4)
+    full = torch.arange(8, dtype=torch.float32).reshape(1, 1, 4, 2)
+    shard = attention.shard_kv_heads(full)
+    torch.testing.assert_close(shard, full[:, :, 2:], rtol=0, atol=0)
+    assert shard.is_contiguous()
+    assert shard.untyped_storage().nbytes() == shard.numel() * shard.element_size()
+
+
+@pytest.mark.parametrize("attention_class", ["LingBotSelfAttention", "LingBotCrossAttention"])
+def test_ulysses_rejects_non_divisible_head_count(monkeypatch, attention_class):
+    module = _load_module()
+    monkeypatch.setattr(
+        module,
+        "get_sp_group",
+        lambda: SimpleNamespace(
+            ulysses_world_size=3,
+            ulysses_rank=0,
+            ulysses_group=None,
+        ),
+    )
+    with pytest.raises(ValueError, match="heads must be divisible"):
+        getattr(module, attention_class)(dim=8, num_heads=4)
diff --git a/tests/diffusion/models/lingbot_world/test_lingbot_world_transformer.py b/tests/diffusion/models/lingbot_world/test_lingbot_world_transformer.py
index e2e2a08b6a6..b4bf7805fe3 100644
--- a/tests/diffusion/models/lingbot_world/test_lingbot_world_transformer.py
+++ b/tests/diffusion/models/lingbot_world/test_lingbot_world_transformer.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 
 from __future__ import annotations
 
@@ -7,14 +7,17 @@
 import inspect
 import json
 import math
+from datetime import timedelta
 from pathlib import Path
+from types import SimpleNamespace
 
 import pytest
 import torch
 
 from tests.diffusion.models.lingbot_world import test_lingbot_world_attention as attention_tests
+from tests.helpers.mark import hardware_test
 
-pytestmark = [pytest.mark.core_model, pytest.mark.diffusion, pytest.mark.cpu]
+pytestmark = [pytest.mark.core_model, pytest.mark.diffusion]
 
 _FIXTURE_PATH = Path(__file__).with_name("fixtures") / "lingbot_world_weight_index_names.json.fixture"
 _SHAPE_FIXTURE_PATH = Path(__file__).with_name("fixtures") / "lingbot_world_official_shapes.json.fixture"
@@ -117,6 +120,7 @@ def _assert_self_cache_unchanged(cache, snapshot) -> None:
         attention_tests._assert_cache_unchanged(layer_cache, layer_snapshot)
 
 
+@pytest.mark.cpu
 def test_tiny_transformer_runs_four_chunks_with_explicit_cache_commit_and_camera_path() -> None:
     torch.manual_seed(7)
     module = attention_tests._load_module()
@@ -191,6 +195,7 @@ def test_tiny_transformer_runs_four_chunks_with_explicit_cache_commit_and_camera
     assert not torch.equal(camera_output, alternate_output)
 
 
+@pytest.mark.cpu
 def test_partial_cross_attention_cache_projects_text_only_for_missing_layers() -> None:
     module = attention_tests._load_module()
     model = _tiny_model(module, num_layers=2).eval()
@@ -229,6 +234,7 @@ def test_partial_cross_attention_cache_projects_text_only_for_missing_layers() -
 
 
 @pytest.mark.parametrize("frames", [1, 6], ids=("partial", "multiple_blocks"))
+@pytest.mark.cpu
 def test_forward_rejects_chunks_that_do_not_equal_configured_block_size(frames: int) -> None:
     module = attention_tests._load_module()
     model = _tiny_model(
@@ -257,6 +263,7 @@ def test_forward_rejects_chunks_that_do_not_equal_configured_block_size(frames:
     assert cache.cross_attention == [None]
 
 
+@pytest.mark.cpu
 def test_forward_accepts_exactly_one_configured_frame_block() -> None:
     module = attention_tests._load_module()
     model = _tiny_model(
@@ -279,6 +286,7 @@ def test_forward_accepts_exactly_one_configured_frame_block() -> None:
     assert output.shape == (1, 2, 3, 4, 4)
 
 
+@pytest.mark.cpu
 def test_transformer_allocates_request_cache_from_its_configured_geometry() -> None:
     module = attention_tests._load_module()
     model = _tiny_model(
@@ -303,6 +311,7 @@ def test_transformer_allocates_request_cache_from_its_configured_geometry() -> N
     assert all(layer.value.shape == (2, 6 * 4 * 6, 2, 2) for layer in cache.self_attention)
 
 
+@pytest.mark.cpu
 def test_video_patch_embedding_uses_temporal_height_width_token_order() -> None:
     module = attention_tests._load_module()
     model = _tiny_model(module, num_layers=1, num_frames_per_block=2)
@@ -323,6 +332,7 @@ def test_video_patch_embedding_uses_temporal_height_width_token_order() -> None:
     torch.testing.assert_close(tokens[0, :, 0], torch.tensor([1.0, 3.0, 9.0, 11.0]))
 
 
+@pytest.mark.cpu
 def test_unpatchify_restores_two_frame_channel_and_spatial_order() -> None:
     module = attention_tests._load_module()
     model = _tiny_model(module, num_layers=1, num_frames_per_block=2)
@@ -363,6 +373,7 @@ def test_unpatchify_restores_two_frame_channel_and_spatial_order() -> None:
     torch.testing.assert_close(output, expected)
 
 
+@pytest.mark.cpu
 def test_head_modulation_broadcasts_distinct_condition_per_frame() -> None:
     module = attention_tests._load_module()
     model = _tiny_model(module, num_layers=1, num_frames_per_block=2)
@@ -381,6 +392,7 @@ def test_head_modulation_broadcasts_distinct_condition_per_frame() -> None:
     torch.testing.assert_close(output, expected)
 
 
+@pytest.mark.cpu
 def test_constructor_defaults_match_official_checkpoint_config() -> None:
     module = attention_tests._load_module()
     parameters = inspect.signature(module.CausalLingBotWorldTransformer3DModel.__init__).parameters
@@ -406,6 +418,7 @@ def test_constructor_defaults_match_official_checkpoint_config() -> None:
     assert {name: parameters[name].default for name in expected} == expected
 
 
+@pytest.mark.cpu
 def test_transformer_exposes_parameter_dtype_for_pipeline_runtime() -> None:
     module = attention_tests._load_module()
     model = _tiny_model(module)
@@ -413,12 +426,14 @@ def test_transformer_exposes_parameter_dtype_for_pipeline_runtime() -> None:
     assert model.dtype == next(model.parameters()).dtype
 
 
+@pytest.mark.cpu
 def test_transformer_declares_regional_compile_block() -> None:
     module = attention_tests._load_module()
 
     assert module.CausalLingBotWorldTransformer3DModel._repeated_blocks == ["LingBotAttentionBlock"]
 
 
+@pytest.mark.cpu
 def test_lingbot_rms_norm_uses_global_tp_square_mean(monkeypatch) -> None:
     module = attention_tests._load_module()
     reduced_values: list[torch.Tensor] = []
@@ -440,6 +455,7 @@ def all_reduce(value: torch.Tensor) -> torch.Tensor:
     torch.testing.assert_close(reduced_values[0], torch.tensor([[25.0]]))
 
 
+@pytest.mark.cpu
 def test_attention_rejects_heads_not_divisible_by_tp_size(monkeypatch) -> None:
     module = attention_tests._load_module()
     monkeypatch.setattr(module, "get_tensor_model_parallel_world_size", lambda: 3)
@@ -448,6 +464,7 @@ def test_attention_rejects_heads_not_divisible_by_tp_size(monkeypatch) -> None:
         module.LingBotSelfAttention(dim=4, num_heads=2)
 
 
+@pytest.mark.cpu
 def test_constructor_rejects_unsupported_qk_norm_with_config_error() -> None:
     module = attention_tests._load_module()
 
@@ -456,6 +473,7 @@ def test_constructor_rejects_unsupported_qk_norm_with_config_error() -> None:
 
 
 @pytest.mark.parametrize("field", ["image_dim", "added_kv_proj_dim", "pos_embed_seq_len"])
+@pytest.mark.cpu
 def test_constructor_rejects_non_null_image_embedding_fields(field: str) -> None:
     module = attention_tests._load_module()
 
@@ -463,6 +481,7 @@ def test_constructor_rejects_non_null_image_embedding_fields(field: str) -> None
         module.CausalLingBotWorldTransformer3DModel(**{field: 4})
 
 
+@pytest.mark.cpu
 def test_constructor_rejects_unsupported_quantization_with_runtime_error() -> None:
     module = attention_tests._load_module()
 
@@ -470,6 +489,7 @@ def test_constructor_rejects_unsupported_quantization_with_runtime_error() -> No
         module.CausalLingBotWorldTransformer3DModel(quant_config=object())
 
 
+@pytest.mark.cpu
 def test_from_config_accepts_diffusers_metadata_and_normalizes_patch_size() -> None:
     module = attention_tests._load_module()
 
@@ -522,6 +542,7 @@ def __init__(self, **kwargs) -> None:
         ("sink_size", 0),
     ],
 )
+@pytest.mark.cpu
 def test_from_config_rejects_checkpoint_topology_drift(field: str, value: object) -> None:
     module = attention_tests._load_module()
     config = {
@@ -554,6 +575,7 @@ def test_from_config_rejects_checkpoint_topology_drift(field: str, value: object
         module.CausalLingBotWorldTransformer3DModel.from_config(config)
 
 
+@pytest.mark.cpu
 def test_from_config_ignores_non_semantic_checkpoint_metadata() -> None:
     module = attention_tests._load_module()
     config = {
@@ -569,6 +591,7 @@ def test_from_config_ignores_non_semantic_checkpoint_metadata() -> None:
     assert model.config.num_layers == 40
 
 
+@pytest.mark.cpu
 def test_load_weights_uses_parameter_loaders_and_rejects_unknown_model_keys() -> None:
     module = attention_tests._load_module()
     model = _tiny_model(module, num_layers=1)
@@ -606,6 +629,7 @@ def record_loader(param: torch.Tensor, loaded_weight: torch.Tensor, shard_id: st
         model.load_weights([("unexpected_model.weight", torch.ones(1))])
 
 
+@pytest.mark.cpu
 def test_load_weights_consumes_checkpoint_iterator_incrementally() -> None:
     module = attention_tests._load_module()
     model = _tiny_model(module, num_layers=1)
@@ -619,6 +643,7 @@ def weights():
     assert model.load_weights(weights()) == {first_name}
 
 
+@pytest.mark.cpu
 def test_real_auto_weights_loader_covers_fused_model_parameter_namespace() -> None:
     utils = pytest.importorskip("vllm.model_executor.models.utils")
     module = attention_tests._load_module()
@@ -638,6 +663,7 @@ def __init__(self) -> None:
     assert set(dict(pipeline.named_parameters())) <= loaded
 
 
+@pytest.mark.cpu
 def test_checkpoint_weight_index_fixture_matches_model_namespaces() -> None:
     module = attention_tests._load_module()
     fixture = json.loads(_FIXTURE_PATH.read_text())
@@ -667,6 +693,7 @@ def test_checkpoint_weight_index_fixture_matches_model_namespaces() -> None:
     assert all(len(shard["parameter_names_sha256"]) == 64 for shard in fixture["shards"].values())
 
 
+@pytest.mark.cpu
 def test_official_default_shapes_match_public_safetensors_header_fixture() -> None:
     module = attention_tests._load_module()
     fixture = json.loads(_SHAPE_FIXTURE_PATH.read_text())
@@ -683,3 +710,284 @@ def test_official_default_shapes_match_public_safetensors_header_fixture() -> No
         shape, dtype = parameter_specs[name]
         assert tuple(shape) == tuple(expected_shape), name
         assert dtype == expected_dtype
+
+
+@pytest.mark.cpu
+def test_timestep_expansion_only_runs_with_ulysses(monkeypatch):
+    dtype = torch.bfloat16
+    module = attention_tests._load_module()
+    hidden = torch.randn(2, 12, 4).to(dtype)
+    camera = torch.randn_like(hidden)
+    table = torch.randn(2, 3, 6, 4).to(dtype)
+    rotary = (torch.randn(12, 2), torch.randn(12, 2))
+    prepare = module._LingBotSPPrepare()
+    assert prepare(hidden, camera, table, rotary)[2] is table
+    monkeypatch.setattr(module, "get_sp_group", lambda: SimpleNamespace(ulysses_world_size=2))
+    expanded = prepare(hidden, camera, table, rotary)[2]
+    assert expanded.shape == (2, 12, 6, 4)
+    torch.testing.assert_close(expanded, table.repeat_interleave(4, dim=1), rtol=0, atol=0)
+
+
+@pytest.mark.parametrize("unsharded", [None, 3], ids=["missing-hook", "unsharded-rope"])
+@pytest.mark.cpu
+def test_missing_or_partial_sp_split_fails_before_attention(monkeypatch, unsharded):
+    module = attention_tests._load_module()
+    model = _tiny_model(module, num_frames_per_block=3, sliding_window_num_frames=6)
+    cache = _cache(module, model)
+    for block in model.blocks:
+        block.self_attn.ulysses_world_size = 2
+    monkeypatch.setattr(module, "get_sp_group", lambda: SimpleNamespace(ulysses_world_size=2))
+    original = model.sp_prepare.forward
+
+    def partial_split(*args):
+        values = original(*args)
+        if unsharded is None:
+            return values
+        return tuple(
+            value if i == unsharded else value.chunk(2, dim=1 if i < 3 else 0)[0] for i, value in enumerate(values)
+        )
+
+    monkeypatch.setattr(model.sp_prepare, "forward", partial_split)
+
+    def forbidden(*args, **kwargs):
+        raise AssertionError("attention/collectives must not run before shard validation")
+
+    monkeypatch.setattr(model.blocks[0], "forward", forbidden)
+    with pytest.raises(RuntimeError, match="SP input hooks"):
+        model(
+            torch.randn(1, 36, 3, 4, 4),
+            torch.tensor([1.0]),
+            torch.randn(1, 3, 6),
+            torch.randn(1, 384, 3, 4, 4),
+            cache=cache,
+            start_frame=0,
+            update_cache=False,
+        )
+
+
+# Real multi-rank regression: synthetic weights, native SP/TP and attention.
+_HEADS, _HEAD_DIM, _LAYERS = 8, 32, 2
+_FRAMES, _SIDE, _TOKENS_PER_FRAME = 3, 32, 256
+
+
+def _model(dtype):
+    from vllm_omni.diffusion.models.lingbot_world.transformer import CausalLingBotWorldTransformer3DModel
+
+    model = CausalLingBotWorldTransformer3DModel(
+        num_attention_heads=_HEADS,
+        attention_head_dim=_HEAD_DIM,
+        num_layers=_LAYERS,
+        in_channels=4,
+        out_channels=4,
+        text_dim=8,
+        freq_dim=16,
+        ffn_dim=512,
+        patch_size=(1, 2, 2),
+        sink_size=1,
+        num_frames_per_block=_FRAMES,
+        sliding_window_num_frames=6,
+        rope_max_seq_len=32,
+    ).eval()
+    return model.to(device=torch.device("cuda", torch.accelerator.current_device_index()), dtype=dtype)
+
+
+def _checkpoint(model):
+    weights = {}
+    generator = torch.Generator().manual_seed(17)
+    for name, param in sorted(model.named_parameters()):
+        data = torch.randn(param.shape, generator=generator) * 0.02
+        if "norm" in name and name.endswith("weight"):
+            data.fill_(1)
+        if name.endswith("modulation") and data.shape[-2] == 6:
+            data[..., 2, :] = 1
+            data[..., 5, :] = 1
+        data = data.to(param.dtype)
+        param.copy_(data)
+        if ".self_attn.qkv." in name:
+            for component, chunk in zip(("q", "k", "v"), data.chunk(3), strict=True):
+                weights[name.replace(".self_attn.qkv.", f".self_attn.{component}.")] = chunk
+        else:
+            weights[name] = data
+    return weights
+
+
+def _rollout(model, mode, dtype, batch):
+    from vllm_omni.diffusion.models.lingbot_world.transformer import LingBotTransformerCache
+    from vllm_omni.experimental.ar_diffusion.capability import ARDiffusionKVBranchSpec
+    from vllm_omni.experimental.ar_diffusion.kv_cache import ARDiffusionKVCache, ARDiffusionKVConfig
+    from vllm_omni.experimental.ar_diffusion.kv_cache.state import ARDiffusionKVState
+
+    device = next(model.parameters()).device
+    state = None
+    if mode == "paged":
+        kv = ARDiffusionKVCache(
+            ARDiffusionKVConfig(enable=True, chunk_size=_TOKENS_PER_FRAME, window_chunks=5, sink_chunks=1),
+            num_layers=_LAYERS,
+            num_kv_heads=model.blocks[0].self_attn.num_sp_heads,
+            head_size=_HEAD_DIM,
+            dtype=dtype,
+            block_size=_TOKENS_PER_FRAME,
+            max_model_len=4096,
+            available_bytes=1 << 27,
+            kv_branches=(ARDiffusionKVBranchSpec("main", 0),),
+            session_capacity=1,
+            frames_per_block=_FRAMES,
+            max_scratch_tokens_per_branch=_FRAMES * _TOKENS_PER_FRAME,
+            cross_attention_lengths={"text": 5},
+            device=device,
+        )
+        state = ARDiffusionKVState(kv, "numeric", {"main": kv.begin_request("numeric")}, num_layers=_LAYERS)
+        cache = LingBotTransformerCache(self_attention=[], cross_attention=[None] * _LAYERS)
+    else:
+        cache = model.allocate_cache(
+            batch_size=batch, latent_height=_SIDE, latent_width=_SIDE, device=device, dtype=dtype
+        )
+    generator = torch.Generator().manual_seed(123)
+    text = torch.randn(batch, 5, 8, generator=generator).to(device, dtype)
+    outputs = []
+    try:
+        for start in range(0, 12, _FRAMES):
+            latent = torch.randn(batch, 4, _FRAMES, _SIDE, _SIDE, generator=generator).to(device, dtype)
+            camera = torch.randn(batch, 384, _FRAMES, _SIDE, _SIDE, generator=generator).to(device, dtype)
+            for commit in (False, False, True):
+                if state is not None:
+                    cache.self_attention = state.get_kv_caches(
+                        "main", seq_len=_FRAMES * _TOKENS_PER_FRAME, commit_current=commit
+                    )
+                output = model(
+                    latent,
+                    torch.tensor([100.0, 400.0, 900.0], device=device).expand(batch, -1),
+                    text,
+                    camera,
+                    cache=cache,
+                    start_frame=start,
+                    update_cache=commit,
+                )
+                outputs.append(output.float().cpu())
+                if state is not None:
+                    if not state.is_cross_attention_populated("main", "text"):
+                        state.populate_cross_attention(
+                            "main", "text", [(layer.key, layer.value) for layer in cache.cross_attention]
+                        )
+                        for layer, pool in zip(
+                            cache.cross_attention, state.get_cross_attention_kv("main", "text"), strict=True
+                        ):
+                            layer.key, layer.value = pool["k"], pool["v"]
+                    state.commit_paged_context("main")
+        cross = [
+            (layer.key.detach().float().cpu(), layer.value.detach().float().cpu()) for layer in cache.cross_attention
+        ]
+        return torch.stack(outputs), cross
+    finally:
+        if state is not None:
+            state.close()
+
+
+def _worker(rank, world_size, sp_size, tp_size, mode, dtype, batch, rendezvous):
+    from vllm.config import VllmConfig
+    from vllm.config.vllm import set_current_vllm_config
+    from vllm.distributed import get_tensor_model_parallel_rank
+
+    from vllm_omni.diffusion.config import set_current_diffusion_config
+    from vllm_omni.diffusion.data import AttentionConfig, AttentionSpec, DiffusionParallelConfig, OmniDiffusionConfig
+    from vllm_omni.diffusion.distributed.parallel_state import (
+        destroy_distributed_env,
+        destroy_model_parallel,
+        get_sp_group,
+        init_distributed_environment,
+        initialize_model_parallel,
+    )
+    from vllm_omni.diffusion.forward_context import set_forward_context
+    from vllm_omni.diffusion.registry import _apply_sequence_parallel_if_enabled
+    from vllm_omni.platforms import current_omni_platform
+
+    current_omni_platform.set_device(torch.device("cuda", rank))
+    torch.backends.cuda.matmul.allow_tf32 = False
+    torch.backends.cudnn.allow_tf32 = False
+    torch.distributed.init_process_group(
+        "nccl", init_method=f"file://{rendezvous}", world_size=world_size, rank=rank, timeout=timedelta(seconds=90)
+    )
+    init_distributed_environment(world_size=world_size, rank=rank, local_rank=rank, backend="nccl")
+    try:
+        with torch.inference_mode(), set_current_vllm_config(VllmConfig()):
+            for baseline in (True, False):
+                sp, tp = (1, 1) if baseline else (sp_size, tp_size)
+                initialize_model_parallel(
+                    data_parallel_size=world_size // (sp * tp),
+                    sequence_parallel_size=sp,
+                    ulysses_degree=sp,
+                    tensor_parallel_size=tp,
+                )
+                config = OmniDiffusionConfig(
+                    model=str(Path(rendezvous).parent),
+                    dtype=dtype,
+                    enforce_eager=True,
+                    parallel_config=DiffusionParallelConfig(
+                        data_parallel_size=world_size // (sp * tp),
+                        sequence_parallel_size=sp,
+                        ulysses_degree=sp,
+                        tensor_parallel_size=tp,
+                    ),
+                    diffusion_attention_config=AttentionConfig(default=AttentionSpec(backend="TORCH_SDPA")),
+                )
+                with set_current_diffusion_config(config), set_forward_context(omni_diffusion_config=config):
+                    model = _model(dtype)
+                    if baseline:
+                        weights = _checkpoint(model)
+                    else:
+                        model.load_weights(iter(weights.items()))
+                    _apply_sequence_parallel_if_enabled(SimpleNamespace(transformer=model), config)
+                    result, cross = _rollout(model, mode, dtype, batch)
+                    if baseline:
+                        expected, expected_cross = result, cross
+                    else:
+                        assert expected.abs().max() > 1e-3
+                        bound = 1e-5 if dtype == torch.float32 else 1e-2
+                        error = (result - expected).double().norm() / expected.double().norm()
+                        assert error <= bound, f"rank={rank}, TP{tp} SP{sp}: relative L2 {error.item():.3g} > {bound}"
+                        local_heads = _HEADS // tp // sp
+                        first = (
+                            get_tensor_model_parallel_rank() * (_HEADS // tp)
+                            + get_sp_group().ulysses_rank * local_heads
+                        )
+                        for (k, v), (ek, ev) in zip(cross, expected_cross, strict=True):
+                            tolerance = 1e-5 if dtype == torch.float32 else 2e-2
+                            torch.testing.assert_close(
+                                k, ek[:, :, first : first + local_heads], rtol=tolerance, atol=tolerance
+                            )
+                            torch.testing.assert_close(
+                                v, ev[:, :, first : first + local_heads], rtol=tolerance, atol=tolerance
+                            )
+                        if rank == 0:
+                            print(f"{mode} {dtype} TP{tp} SP{sp}: relative L2={error.item():.3g}", flush=True)
+                    del model
+                torch.distributed.barrier()
+                destroy_model_parallel()
+    finally:
+        destroy_distributed_env()
+
+
+def _run(tmp_path: Path, sp, tp, mode, dtype, batch):
+    if torch.accelerator.device_count() < sp * tp:
+        pytest.skip(f"requires {sp * tp} GPUs")
+    torch.multiprocessing.spawn(
+        _worker, args=(sp * tp, sp, tp, mode, dtype, batch, str(tmp_path / "rendezvous")), nprocs=sp * tp
+    )
+
+
+@pytest.mark.parallel
+@hardware_test(res={"cuda": "L4"}, num_cards=2)
+def test_sp2_direct_matches_sp1_fp32(tmp_path):
+    _run(tmp_path, 2, 1, "direct", torch.float32, 2)
+
+
+@pytest.mark.parallel
+@hardware_test(res={"cuda": "L4"}, num_cards=4)
+def test_sp4_direct_matches_sp1_bf16(tmp_path):
+    _run(tmp_path, 4, 1, "direct", torch.bfloat16, 1)
+
+
+@pytest.mark.parallel
+@hardware_test(res={"cuda": "L4"}, num_cards=4)
+def test_tp2_sp2_paged_matches_sp1_bf16(tmp_path):
+    _run(tmp_path, 2, 2, "paged", torch.bfloat16, 1)
diff --git a/tests/diffusion/models/lingbot_world/test_pipeline_lingbot_world.py b/tests/diffusion/models/lingbot_world/test_pipeline_lingbot_world.py
index 52113208a74..a58eee935db 100644
--- a/tests/diffusion/models/lingbot_world/test_pipeline_lingbot_world.py
+++ b/tests/diffusion/models/lingbot_world/test_pipeline_lingbot_world.py
@@ -126,8 +126,6 @@ def __init__(self, *, raise_on_call: int | None = None, dtype: torch.dtype = tor
             sink_size=3,
         )
         self.blocks = nn.ModuleList([nn.Identity(), nn.Identity()])
-        for block in self.blocks:
-            block.self_attn = SimpleNamespace(num_local_heads=2, head_dim=4)
         self.calls: list[dict] = []
         self.cache_allocations: list[dict] = []
         self.raise_on_call = raise_on_call
@@ -387,6 +385,9 @@ def _od_config(**overrides):
         "parallel_config": SimpleNamespace(
             pipeline_parallel_size=1,
             sequence_parallel_size=1,
+            ulysses_degree=1,
+            ring_degree=1,
+            allgather_degree=1,
             cfg_parallel_size=1,
             vae_patch_parallel_size=1,
             use_hsdp=False,
@@ -438,15 +439,15 @@ def test_pipeline_respects_loader_managed_component_placement(offload_field: str
     assert getattr(pipeline.vae, "to_calls", []) == []
 
 
-def test_ar_diffusion_capability_uses_fixed_tp_local_lingbot_geometry() -> None:
+def test_ar_diffusion_capability_uses_transformer_local_head_geometry() -> None:
     module = _load_pipeline_module()
-    module.get_tensor_model_parallel_world_size = lambda: 1
     pipeline = _pipeline(module)
-
+    # Use the constructed head count even when the config describes a different geometry.
+    pipeline.transformer.blocks[0].self_attn = SimpleNamespace(num_sp_heads=1)
     spec = pipeline.ar_diffusion_kv_cache_spec()
 
     assert spec.num_layers == 2
-    assert spec.num_kv_heads == 2
+    assert spec.num_kv_heads == 1
     assert spec.head_size == 4
     assert spec.tokens_per_frame == 1
     assert spec.frames_per_block == 3
@@ -604,7 +605,6 @@ def test_component_discovery_uses_official_checkpoint_contract() -> None:
     ("field", "value", "feature"),
     [
         ("pipeline_parallel_size", 2, "pipeline parallelism"),
-        ("sequence_parallel_size", 2, "sequence parallelism"),
         ("cfg_parallel_size", 2, "CFG parallelism"),
         ("vae_patch_parallel_size", 2, "VAE parallelism"),
         ("use_hsdp", True, "HSDP"),
@@ -622,6 +622,43 @@ def test_unsupported_parallel_modes_fail_before_component_loading(field: str, va
     assert module._loader_state.prefetch_calls == []
 
 
+def test_pure_ulysses_parallel_config_is_supported() -> None:
+    module = _load_pipeline_module()
+    parallel_config = _od_config().parallel_config
+    parallel_config.sequence_parallel_size = 2
+    parallel_config.ulysses_degree = 2
+
+    pipeline = module.LingBotWorldCausalDMDPipeline(od_config=_od_config(parallel_config=parallel_config))
+
+    assert pipeline.transformer is not None
+
+
+@pytest.mark.parametrize(
+    "overrides",
+    [
+        {"sequence_parallel_size": 4, "ring_degree": 2},  # Normalized hybrid.
+        {"ulysses_degree": 1, "allgather_degree": 2},  # Normalized AllGather-KV.
+        {"ring_degree": 2},  # Isolate each clause from the SP-size mismatch.
+        {"allgather_degree": 2},
+        {"ulysses_mode": "advanced_uaa"},
+        {"ulysses_a2a_permute": True},
+        {"ulysses_degree": None},  # Missing degree must not imply pure Ulysses.
+    ],
+)
+def test_unsupported_sp_config_fails_before_component_loading(overrides):
+    module = _load_pipeline_module()
+    config = _od_config().parallel_config
+    config.sequence_parallel_size = config.ulysses_degree = 2
+    for name, value in overrides.items():
+        if value is None:
+            delattr(config, name)
+        else:
+            setattr(config, name, value)
+    with pytest.raises(NotImplementedError, match="pure Ulysses"):
+        module.LingBotWorldCausalDMDPipeline(od_config=_od_config(parallel_config=config))
+    assert module._loader_state.prefetch_calls == []
+
+
 def test_unsupported_quantization_fails_before_component_loading() -> None:
     module = _load_pipeline_module()
 
diff --git a/tests/examples/offline_inference/test_lingbot_world_v2.py b/tests/examples/offline_inference/test_lingbot_world_v2.py
new file mode 100644
index 00000000000..41d2e73b712
--- /dev/null
+++ b/tests/examples/offline_inference/test_lingbot_world_v2.py
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
+
+from pathlib import Path
+
+import pytest
+
+from examples.offline_inference.diffusion import lingbot_world_v2 as example
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu, pytest.mark.diffusion]
+
+
+def test_offline_ulysses_argument(tmp_path):
+    argv = ["--image", "frame.jpg", "--action-dir", "forward", "--prompt", "A lake"]
+    paths = example.LingBotPaths(
+        tmp_path / "frame.jpg", tmp_path / "forward", tmp_path, Path("forward"), 9, tmp_path / "out.mp4"
+    )
+    assert example.parse_args(argv).ulysses_degree == 1
+    args = example.parse_args([*argv, "--ulysses-degree", "4"])
+    kwargs = example.build_omni_kwargs(args, paths)
+    assert kwargs["ulysses_degree"] == 4 and kwargs["tensor_parallel_size"] == 1
+    args.ulysses_degree = 0
+    with pytest.raises(ValueError, match="--ulysses-degree"):
+        example.build_omni_kwargs(args, paths)
diff --git a/vllm_omni/diffusion/models/lingbot_world/pipeline.py b/vllm_omni/diffusion/models/lingbot_world/pipeline.py
index b41abd861d6..d2dfde3d4e9 100644
--- a/vllm_omni/diffusion/models/lingbot_world/pipeline.py
+++ b/vllm_omni/diffusion/models/lingbot_world/pipeline.py
@@ -18,7 +18,6 @@
 from diffusers.utils.torch_utils import randn_tensor
 from torch import nn
 from transformers import AutoTokenizer, UMT5EncoderModel
-from vllm.distributed import get_tensor_model_parallel_world_size
 from vllm.model_executor.models.utils import AutoWeightsLoader
 
 from vllm_omni.diffusion.data import DiffusionOutput, OmniDiffusionConfig
@@ -203,7 +202,6 @@ def _validate_parallel_config(od_config: OmniDiffusionConfig) -> None:
         return
     unsupported_sizes = {
         "pipeline_parallel_size": "pipeline parallelism",
-        "sequence_parallel_size": "sequence parallelism",
         "cfg_parallel_size": "CFG parallelism",
         "vae_patch_parallel_size": "VAE parallelism",
     }
@@ -211,6 +209,25 @@ def _validate_parallel_config(od_config: OmniDiffusionConfig) -> None:
         size = getattr(parallel_config, field, 1) or 1
         if size > 1:
             raise NotImplementedError(f"LingBot World v1 does not support {feature} ({field}={size}).")
+    sequence_parallel_size = getattr(parallel_config, "sequence_parallel_size", 1) or 1
+    ulysses_degree = getattr(parallel_config, "ulysses_degree", 1) or 1
+    ring_degree = getattr(parallel_config, "ring_degree", 1) or 1
+    allgather_degree = getattr(parallel_config, "allgather_degree", 1) or 1
+    ulysses_mode = getattr(parallel_config, "ulysses_mode", "strict")
+    ulysses_a2a_permute = bool(getattr(parallel_config, "ulysses_a2a_permute", False))
+    if (
+        sequence_parallel_size != ulysses_degree
+        or ring_degree != 1
+        or allgather_degree != 1
+        or ulysses_mode != "strict"
+        or ulysses_a2a_permute
+    ):
+        raise NotImplementedError(
+            "LingBot World sequence parallelism requires pure Ulysses with ulysses_a2a_permute disabled: "
+            f"sequence_parallel_size={sequence_parallel_size}, ulysses_degree={ulysses_degree}, "
+            f"ring_degree={ring_degree}, allgather_degree={allgather_degree}, ulysses_mode={ulysses_mode!r}, "
+            f"ulysses_a2a_permute={ulysses_a2a_permute}."
+        )
     if getattr(parallel_config, "use_hsdp", False):
         raise NotImplementedError("LingBot World v1 does not support HSDP.")
     if getattr(parallel_config, "enable_expert_parallel", False):
@@ -557,8 +574,6 @@ def ar_diffusion_kv_cache_spec(self) -> ARDiffusionKVCacheSpec:
         latent_height = self._ar_height // spatial
         latent_width = self._ar_width // spatial
         tokens_per_frame = (latent_height // patch_height) * (latent_width // patch_width)
-        tp_size = get_tensor_model_parallel_world_size()
-        num_local_heads = int(self.transformer.config.num_attention_heads) // tp_size
         total_window_frames = (
             int(self.transformer.config.local_attn_size)
             if int(self.transformer.config.local_attn_size) != -1
@@ -579,7 +594,7 @@ def ar_diffusion_kv_cache_spec(self) -> ARDiffusionKVCacheSpec:
         )
         return ARDiffusionKVCacheSpec(
             num_layers=int(self.transformer.config.num_layers),
-            num_kv_heads=num_local_heads,
+            num_kv_heads=int(self.transformer.blocks[0].self_attn.num_sp_heads),
             head_size=int(self.transformer.config.attention_head_dim),
             tokens_per_frame=tokens_per_frame,
             frames_per_block=int(self.transformer.config.num_frames_per_block),
@@ -960,20 +975,11 @@ def _ar_text_caches(
             def layer_kv() -> Iterator[tuple[torch.Tensor, torch.Tensor]]:
                 for block in self.transformer.blocks:
                     cross_attention = block.cross_attn
-                    key = cross_attention.norm_k(cross_attention.k(projected_text)).unflatten(
-                        2,
-                        (
-                            cross_attention.num_local_heads,
-                            cross_attention.head_dim,
-                        ),
-                    )
-                    value = cross_attention.v(projected_text).unflatten(
-                        2,
-                        (
-                            cross_attention.num_local_heads,
-                            cross_attention.head_dim,
-                        ),
+                    shape = (cross_attention.num_local_heads, cross_attention.head_dim)
+                    key = cross_attention.shard_kv_heads(
+                        cross_attention.norm_k(cross_attention.k(projected_text)).unflatten(2, shape)
                     )
+                    value = cross_attention.shard_kv_heads(cross_attention.v(projected_text).unflatten(2, shape))
                     yield key, value
 
             state.populate_cross_attention(
diff --git a/vllm_omni/diffusion/models/lingbot_world/transformer.py b/vllm_omni/diffusion/models/lingbot_world/transformer.py
index 35ec1880112..32931db0c9e 100644
--- a/vllm_omni/diffusion/models/lingbot_world/transformer.py
+++ b/vllm_omni/diffusion/models/lingbot_world/transformer.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 """Checkpoint-compatible causal DiT for the LingBot World v2 model package."""
 
 from __future__ import annotations
@@ -24,6 +24,9 @@
 from vllm.model_executor.utils import set_weight_attrs
 
 from vllm_omni.diffusion.attention.layer import Attention
+from vllm_omni.diffusion.distributed.comm import SeqAllToAll4D
+from vllm_omni.diffusion.distributed.parallel_state import get_sp_group
+from vllm_omni.diffusion.distributed.sp_plan import SequenceParallelInput, SequenceParallelOutput
 from vllm_omni.diffusion.layers.norm import LayerNorm
 from vllm_omni.diffusion.layers.rope import RotaryEmbeddingWan
 from vllm_omni.experimental.ar_diffusion.kv_cache.paged_attention import (
@@ -127,6 +130,37 @@ def _projection_prefix(prefix: str, name: str) -> str:
     return f"{prefix}.{name}" if prefix else name
 
 
+def _ulysses_state() -> tuple[int, int, torch.distributed.ProcessGroup | None]:
+    coordinator = get_sp_group()
+    return (
+        int(coordinator.ulysses_world_size),
+        int(coordinator.ulysses_rank),
+        coordinator.ulysses_group,
+    )
+
+
+class _LingBotSPPrepare(nn.Module):
+    """Expand frame conditioning only when Ulysses shards the token sequence."""
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        camera_hidden_states: torch.Tensor,
+        timestep_projection: torch.Tensor,
+        rotary_emb: tuple[torch.Tensor, torch.Tensor],
+    ) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]:
+        num_frames = timestep_projection.shape[1]
+        if hidden_states.shape[1] % num_frames:
+            raise ValueError("LingBot token count must be divisible by the latent frame count.")
+        tokens_per_frame = hidden_states.shape[1] // num_frames
+        if get_sp_group().ulysses_world_size > 1:
+            timestep_projection = (
+                timestep_projection.unsqueeze(2).expand(-1, -1, tokens_per_frame, -1, -1).flatten(1, 2)
+            )
+        cosine, sine = rotary_emb
+        return hidden_states, camera_hidden_states, timestep_projection, cosine, sine
+
+
 class LingBotSelfAttention(nn.Module):
     """Block-causal self-attention over retained history and one full chunk."""
 
@@ -157,6 +191,13 @@ def __init__(
             prefix=_projection_prefix(prefix, "qkv"),
         )
         self.num_local_heads = self.qkv.num_heads
+        self.ulysses_world_size, self.ulysses_rank, self.ulysses_group = _ulysses_state()
+        if self.num_local_heads % self.ulysses_world_size:
+            raise ValueError(
+                "LingBot local attention heads must be divisible by the Ulysses degree: "
+                f"heads={self.num_local_heads}, ulysses={self.ulysses_world_size}."
+            )
+        self.num_sp_heads = self.num_local_heads // self.ulysses_world_size
         self.tp_inner_dim = self.num_local_heads * self.head_dim
         self.o = RowParallelLinear(
             dim,
@@ -170,9 +211,9 @@ def __init__(
         self.norm_k = _LingBotRMSNorm(self.tp_inner_dim, eps)
         self.rotary_embedding = RotaryEmbeddingWan(is_neox_style=False, half_head_dim=True)
         self.attn = Attention(
-            num_heads=self.num_local_heads,
+            num_heads=self.num_sp_heads,
             head_size=self.head_dim,
-            num_kv_heads=self.num_local_heads,
+            num_kv_heads=self.num_sp_heads,
             softmax_scale=self.head_dim**-0.5,
             causal=False,
             role="self",
@@ -287,6 +328,11 @@ def forward(
             query = self.rotary_embedding(query, cos, sin)
             key = self.rotary_embedding(key, cos, sin)
 
+        if self.ulysses_world_size > 1:
+            query = SeqAllToAll4D.apply(self.ulysses_group, query, 2, 1, False)
+            key = SeqAllToAll4D.apply(self.ulysses_group, key, 2, 1, False)
+            value = SeqAllToAll4D.apply(self.ulysses_group, value, 2, 1, False)
+
         if isinstance(cache, ARDiffusionPagedLayerInputs):
             if query.shape[0] != 1:
                 raise RuntimeError("LingBot AR-Diffusion paged attention requires batch_size=1.")
@@ -347,6 +393,8 @@ def forward(
                 )
             else:
                 output = self.attn(query, visible_key, visible_value)
+        if self.ulysses_world_size > 1:
+            output = SeqAllToAll4D.apply(self.ulysses_group, output, 1, 2, False)
         return self.o(output.flatten(2, 3))
 
 
@@ -373,6 +421,13 @@ def __init__(
         self.num_heads = num_heads
         self.head_dim = dim // num_heads
         self.num_local_heads = num_heads // tp_size
+        self.ulysses_world_size, self.ulysses_rank, self.ulysses_group = _ulysses_state()
+        if self.num_local_heads % self.ulysses_world_size:
+            raise ValueError(
+                "LingBot local cross-attention heads must be divisible by the Ulysses degree: "
+                f"heads={self.num_local_heads}, ulysses={self.ulysses_world_size}."
+            )
+        self.num_sp_heads = self.num_local_heads // self.ulysses_world_size
         self.tp_inner_dim = self.num_local_heads * self.head_dim
 
         self.q = ColumnParallelLinear(
@@ -410,9 +465,9 @@ def __init__(
         self.norm_q = _LingBotRMSNorm(self.tp_inner_dim, eps)
         self.norm_k = _LingBotRMSNorm(self.tp_inner_dim, eps)
         self.attn = Attention(
-            num_heads=self.num_local_heads,
+            num_heads=self.num_sp_heads,
             head_size=self.head_dim,
-            num_kv_heads=self.num_local_heads,
+            num_kv_heads=self.num_sp_heads,
             softmax_scale=self.head_dim**-0.5,
             causal=False,
             role="cross",
@@ -422,6 +477,14 @@ def __init__(
             disable_kv_quant=True,
         )
 
+    def shard_kv_heads(self, value: torch.Tensor) -> torch.Tensor:
+        """Select this Ulysses rank's projected K/V heads."""
+
+        if self.ulysses_world_size == 1:
+            return value
+        start = self.ulysses_rank * self.num_sp_heads
+        return value[:, :, start : start + self.num_sp_heads].clone(memory_format=torch.contiguous_format)
+
     def forward(
         self,
         hidden_states: torch.Tensor,
@@ -431,6 +494,8 @@ def forward(
     ) -> tuple[torch.Tensor, LingBotAttentionCache]:
         query = self.norm_q(self.q(hidden_states))
         query = query.unflatten(2, (self.num_local_heads, self.head_dim))
+        if self.ulysses_world_size > 1:
+            query = SeqAllToAll4D.apply(self.ulysses_group, query, 2, 1, False)
 
         # Text K/V is constant within a request and is projected once per layer.
         if cache is None:
@@ -438,8 +503,8 @@ def forward(
                 raise ValueError("encoder_hidden_states are required when the cross-attention cache is empty.")
             key = self.norm_k(self.k(encoder_hidden_states))
             value = self.v(encoder_hidden_states)
-            key = key.unflatten(2, (self.num_local_heads, self.head_dim))
-            value = value.unflatten(2, (self.num_local_heads, self.head_dim))
+            key = self.shard_kv_heads(key.unflatten(2, (self.num_local_heads, self.head_dim)))
+            value = self.shard_kv_heads(value.unflatten(2, (self.num_local_heads, self.head_dim)))
             cache = LingBotAttentionCache(
                 key=key,
                 value=value,
@@ -452,6 +517,8 @@ def forward(
             value = cache.value[:, : cache.end]
 
         output = self.attn(query, key, value)
+        if self.ulysses_world_size > 1:
+            output = SeqAllToAll4D.apply(self.ulysses_group, output, 1, 2, False)
         return self.o(output.flatten(2, 3)), cache
 
 
@@ -540,7 +607,18 @@ def forward(
         rotary_emb: tuple[torch.Tensor, torch.Tensor],
     ) -> tuple[torch.Tensor, LingBotAttentionCache]:
         batch_size, token_count, dim = hidden_states.shape
+        if (
+            timestep_projection.ndim != 4
+            or timestep_projection.shape[0] != batch_size
+            or timestep_projection.shape[2:] != (6, dim)
+        ):
+            raise ValueError("LingBot timestep projection must have shape (batch, frames or tokens, 6, dim).")
         num_frames = timestep_projection.shape[1]
+        if num_frames == 0 or token_count % num_frames:
+            raise ValueError("LingBot timestep projection must align with hidden tokens.")
+        if self.self_attn.ulysses_world_size > 1 and num_frames != token_count:
+            raise ValueError("LingBot Ulysses requires one timestep projection per local token.")
+        # Without SP, broadcast per frame. With SP, each entry represents one token.
         tokens_per_frame = token_count // num_frames
         # Timestep, camera, and text remain separate conditioning paths.
         modulation = self.modulation.unsqueeze(1) + timestep_projection.float()
@@ -635,13 +713,26 @@ def forward(
         self,
         hidden_states: torch.Tensor,
         timestep_embedding: torch.Tensor,
+        *,
+        tokens_per_frame: int | None = None,
+        token_offset: int = 0,
     ) -> torch.Tensor:
         num_frames = timestep_embedding.shape[1]
-        tokens_per_frame = hidden_states.shape[1] // num_frames
         modulation = self.modulation.unsqueeze(1) + timestep_embedding.unsqueeze(2).float()
         shift, scale = modulation.chunk(2, dim=2)
-        normalized = self.norm(hidden_states.float()).unflatten(1, (num_frames, tokens_per_frame))
-        normalized = (normalized * (1 + scale) + shift).flatten(1, 2).to(hidden_states.dtype)
+        normalized = self.norm(hidden_states.float())
+        if tokens_per_frame is None:
+            normalized = normalized.unflatten(1, (num_frames, -1))
+            normalized = (normalized * (1 + scale) + shift).flatten(1, 2)
+        else:
+            # A sequence shard can begin/end inside a frame.
+            frames = (
+                torch.arange(hidden_states.shape[1], device=hidden_states.device) + token_offset
+            ) // tokens_per_frame
+            scale = scale.squeeze(2).index_select(1, frames)
+            shift = shift.squeeze(2).index_select(1, frames)
+            normalized = normalized * (1 + scale) + shift
+        normalized = normalized.to(hidden_states.dtype)
         return self.head(normalized)
 
 
@@ -678,6 +769,16 @@ class CausalLingBotWorldTransformer3DModel(nn.Module):
     _repeated_blocks = ["LingBotAttentionBlock"]
     packed_modules_mapping = {"qkv": ["q", "k", "v"]}
     _layerwise_offload_blocks_attrs = ["blocks"]
+    _sp_plan = {
+        "sp_prepare": {
+            0: SequenceParallelInput(split_dim=1, expected_dims=3, split_output=True),
+            1: SequenceParallelInput(split_dim=1, expected_dims=3, split_output=True),
+            2: SequenceParallelInput(split_dim=1, expected_dims=4, split_output=True),
+            3: SequenceParallelInput(split_dim=0, expected_dims=2, split_output=True),
+            4: SequenceParallelInput(split_dim=0, expected_dims=2, split_output=True),
+        },
+        "sp_output_gather": SequenceParallelOutput(gather_dim=1, expected_dims=3),
+    }
 
     def __init__(
         self,
@@ -768,6 +869,8 @@ def __init__(
             stride=patch_size,
         )
         self.patch_embedding_wancamctrl = _LingBotCameraPatchEmbedding(6 * 8 * 8, dim, patch_size)
+        self.sp_prepare = _LingBotSPPrepare()
+        self.sp_output_gather = nn.Identity()
         self.c2ws_hidden_states_layer1 = ColumnParallelLinear(
             dim,
             dim,
@@ -904,8 +1007,7 @@ def allocate_cache(
             self.config.local_attn_size if self.config.local_attn_size != -1 else self.config.sliding_window_num_frames
         )
         max_tokens = int(window_frames * post_patch_height * post_patch_width)
-        tp_size = get_tensor_model_parallel_world_size()
-        num_local_heads = self.config.num_attention_heads // tp_size
+        num_local_heads = self.blocks[0].self_attn.num_sp_heads
         return allocate_lingbot_cache(
             batch_size=batch_size,
             num_layers=self.config.num_layers,
@@ -1138,6 +1240,33 @@ def forward(
                 query_len=hidden_states.shape[1],
             )
             cache.self_attention = [layer_context.to_layer_inputs() for layer_context in cache.self_attention]
+        sp_size = self.blocks[0].self_attn.ulysses_world_size
+        global_tokens = patched_frames * tokens_per_frame
+        hidden_dim = hidden_states.shape[-1]
+        rope_dim = rotary_emb[0].shape[-1]
+        if global_tokens % sp_size:
+            raise ValueError("LingBot Ulysses requires the token count to be divisible by its degree.")
+        hidden_states, camera_hidden_states, timestep_projection, cosine, sine = self.sp_prepare(
+            hidden_states,
+            camera_hidden_states,
+            timestep_projection,
+            rotary_emb,
+        )
+        if sp_size > 1:
+            local_tokens = global_tokens // sp_size
+            expected_hidden = (batch_size, local_tokens, hidden_dim)
+            if (
+                hidden_states.shape != expected_hidden
+                or camera_hidden_states.shape != expected_hidden
+                or timestep_projection.shape != (batch_size, local_tokens, 6, hidden_dim)
+                or cosine.shape != (local_tokens, rope_dim)
+                or sine.shape != (local_tokens, rope_dim)
+            ):
+                raise RuntimeError(
+                    "LingBot SP input hooks did not shard all conditioning tensors consistently; "
+                    f"expected {local_tokens} tokens per rank. Check SP hook registration and input dimensions."
+                )
+        rotary_emb = (cosine, sine)
         # Phase 3: each layer receives its own cache entry. Text K/V is passed
         # only when absent; the returned cache is stored for subsequent DMD
         # steps and causal blocks in this request.
@@ -1156,9 +1285,17 @@ def forward(
             )
             cache.cross_attention[index] = cross_cache
 
-        # Phase 4: map tokens to per-patch 16-channel flow values and restore
-        # [B, C, F, H, W] for the Pipeline's sampler update.
-        hidden_states = self.head(hidden_states, timestep_embedding)
+        # Phase 4: project local tokens before gathering the much narrower flow values.
+        hidden_states = self.head(
+            hidden_states,
+            timestep_embedding,
+            tokens_per_frame=tokens_per_frame if sp_size > 1 else None,
+            token_offset=get_sp_group().ulysses_rank * (global_tokens // sp_size) if sp_size > 1 else 0,
+        )
+        hidden_states = self.sp_output_gather(hidden_states)
+        projected_dim = self.config.out_channels * math.prod(self.config.patch_size)
+        if sp_size > 1 and hidden_states.shape != (batch_size, global_tokens, projected_dim):
+            raise RuntimeError("LingBot SP output hook did not gather the full projected token sequence.")
         return self._unpatchify(
             hidden_states,
             batch_size=batch_size,