diff --git a/cumulus/client/parachain-inherent/src/mock.rs b/cumulus/client/parachain-inherent/src/mock.rs
index 983c2ed89dbda..6c57396f3453b 100644
--- a/cumulus/client/parachain-inherent/src/mock.rs
+++ b/cumulus/client/parachain-inherent/src/mock.rs
@@ -54,6 +54,8 @@ pub struct MockValidationDataInherentDataProvider<R = ()> {
 	/// The relay block in which this parachain appeared to start. This will be the relay block
 	/// number in para block #P1.
 	pub relay_offset: u32,
+	/// The relay parent offset that determines how many relay parent descendants are required.
+	pub relay_parent_offset: u32,
 	/// The number of relay blocks that elapses between each parablock. Probably set this to 1 or 2
 	/// to simulate optimistic or realistic relay chain behavior.
 	pub relay_blocks_per_para_block: u32,
@@ -230,7 +232,7 @@ impl<R: Send + Sync + GenerateRandomness<u64>> InherentDataProvider
 		sproof_builder.included_para_head = self.current_para_block_head.clone();
 		sproof_builder.num_authorities = 2;
 		let (relay_parent_storage_root, proof, relay_parent_descendants) =
-			sproof_builder.into_state_root_proof_and_descendants(1);
+			sproof_builder.into_state_root_proof_and_descendants(self.relay_parent_offset.into());
 		let parachain_inherent_data = ParachainInherentData {
 			validation_data: PersistedValidationData {
 				parent_head: Default::default(),
diff --git a/cumulus/polkadot-omni-node/lib/src/nodes/aura.rs b/cumulus/polkadot-omni-node/lib/src/nodes/aura.rs
index bbdce78d0121d..9cd0246ceff56 100644
--- a/cumulus/polkadot-omni-node/lib/src/nodes/aura.rs
+++ b/cumulus/polkadot-omni-node/lib/src/nodes/aura.rs
@@ -50,6 +50,7 @@ use cumulus_client_parachain_inherent::MockValidationDataInherentDataProvider;
 use cumulus_client_service::CollatorSybilResistance;
 use cumulus_primitives_core::{
 	relay_chain::ValidationCode, CollectCollationInfo, GetParachainInfo, ParaId,
+	RelayParentOffsetApi,
 };
 use cumulus_relay_chain_interface::{OverseerHandle, RelayChainInterface};
 use futures::{prelude::*, FutureExt};
@@ -430,11 +431,15 @@ where
 				UniqueSaturatedInto::<u32>::unique_saturated_into(*current_para_head.number()) + 1;
 			log::info!("Current block number: {current_block_number}");
 
+			let relay_parent_offset =
+				client.runtime_api().relay_parent_offset(block).unwrap_or_default();
+
 			let mocked_parachain = MockValidationDataInherentDataProvider::<()> {
 				current_para_block: current_block_number,
 				para_id,
 				current_para_block_head,
 				relay_blocks_per_para_block: 1,
+				relay_parent_offset,
 				para_blocks_per_relay_epoch: 10,
 				upgrade_go_ahead: should_send_go_ahead.then(|| {
 					log::info!("Detected pending validation code, sending go-ahead signal.");
diff --git a/prdoc/pr_10658.prdoc b/prdoc/pr_10658.prdoc
new file mode 100644
index 0000000000000..d334b2064e42e
--- /dev/null
+++ b/prdoc/pr_10658.prdoc
@@ -0,0 +1,11 @@
+title: 'Omninode instant seal: Support relay parent offset'
+doc:
+- audience: Node Dev
+  description: |-
+    This brings support for relay parent offset to the omni-node instant seal consensus engine. Before instant seal was not working with relay parent offsets bigger than `0`.
+
+crates:
+- name: cumulus-client-parachain-inherent
+  bump: patch
+- name: polkadot-omni-node-lib
+  bump: patch