diff --git a/qiskit/dagcircuit/dagcircuit.py b/qiskit/dagcircuit/dagcircuit.py
index 1594bffc2797..31bef991cf2c 100644
--- a/qiskit/dagcircuit/dagcircuit.py
+++ b/qiskit/dagcircuit/dagcircuit.py
@@ -24,6 +24,7 @@
 import copy
 import itertools
 import math
+from typing import Generator, Any, List
 
 import numpy as np
 import rustworkx as rx
@@ -84,8 +85,8 @@ def __init__(self):
         self.cregs = OrderedDict()
 
         # List of Qubit/Clbit wires that the DAG acts on.
-        self.qubits = []
-        self.clbits = []
+        self.qubits: List[Qubit] = []
+        self.clbits: List[Clbit] = []
 
         self._global_phase = 0
         self._calibrations = defaultdict(dict)
@@ -1051,7 +1052,7 @@ def _key(x):
 
         return iter(rx.lexicographical_topological_sort(self._multi_graph, key=key))
 
-    def topological_op_nodes(self, key=None):
+    def topological_op_nodes(self, key=None) -> Generator[DAGOpNode, Any, Any]:
         """
         Yield op nodes in topological order.
 
diff --git a/qiskit/dagcircuit/dagnode.py b/qiskit/dagcircuit/dagnode.py
index f470527627e6..85485ca41f62 100644
--- a/qiskit/dagcircuit/dagnode.py
+++ b/qiskit/dagcircuit/dagnode.py
@@ -15,8 +15,9 @@
 """Objects to represent the information at a node in the DAGCircuit."""
 
 import warnings
+from typing import Iterable
 
-from qiskit.circuit import Clbit
+from qiskit.circuit import Qubit, Clbit
 
 
 def _condition_as_indices(operation, bit_indices):
@@ -110,7 +111,7 @@ class DAGOpNode(DAGNode):
 
     __slots__ = ["op", "qargs", "cargs", "sort_key"]
 
-    def __init__(self, op, qargs=(), cargs=()):
+    def __init__(self, op, qargs: Iterable[Qubit] = (), cargs: Iterable[Clbit] = ()):
         """Create an Instruction node"""
         super().__init__()
         self.op = op