diff --git a/src/qiskit_qec/analysis/faultenumerator.py b/src/qiskit_qec/analysis/faultenumerator.py
index 4df31677..7122630d 100644
--- a/src/qiskit_qec/analysis/faultenumerator.py
+++ b/src/qiskit_qec/analysis/faultenumerator.py
@@ -18,7 +18,8 @@
 from qiskit import QuantumCircuit
 from qiskit.converters import circuit_to_dag
 from qiskit.circuit.library import IGate, XGate, YGate, ZGate
-from qiskit import execute, Aer
+from qiskit import execute
+from qiskit_aer import Aer
 
 from qiskit_qec.analysis.extensions import C_FAULT_ENUMERATOR
 
diff --git a/src/qiskit_qec/analysis/faultsampler.py b/src/qiskit_qec/analysis/faultsampler.py
index c7db629e..ae7228bb 100644
--- a/src/qiskit_qec/analysis/faultsampler.py
+++ b/src/qiskit_qec/analysis/faultsampler.py
@@ -7,7 +7,8 @@
 from qiskit.dagcircuit.dagnode import DAGNode
 from qiskit.converters import circuit_to_dag
 from qiskit.circuit.library import IGate, XGate, YGate, ZGate
-from qiskit import execute, Aer
+from qiskit import execute
+from qiskit_aer import Aer
 
 from qiskit_qec.utils.dag import node_name_label
 
diff --git a/src/qiskit_qec/circuits/repetition_code.py b/src/qiskit_qec/circuits/repetition_code.py
index 04b64cb0..63811bd6 100644
--- a/src/qiskit_qec/circuits/repetition_code.py
+++ b/src/qiskit_qec/circuits/repetition_code.py
@@ -24,7 +24,7 @@
 from qiskit import ClassicalRegister, QuantumCircuit, QuantumRegister, transpile
 from qiskit.circuit.library import XGate, RZGate
 from qiskit.transpiler import PassManager, InstructionDurations
-from qiskit.transpiler.passes import DynamicalDecoupling
+from qiskit.transpiler.passes import ALAPScheduleAnalysis, PadDynamicalDecoupling
 
 from qiskit_qec.circuits.code_circuit import CodeCircuit
 from qiskit_qec.utils import DecodingGraphNode, DecodingGraphEdge
@@ -1268,7 +1268,6 @@ def check_nodes(self, nodes, ignore_extra_boundary=False, minimal=False):
             # if neutral for maximal, it's neutral
             # otherwise, it is whatever it is for the minimal
             for c in cs:
-
                 neutral = base_neutral
                 num_errors = num_nodes[c]
                 flipped_logicals = flipped_logicals_all[c]
@@ -1381,9 +1380,10 @@ def transpile(self, backend, echo=("X", "X"), echo_num=(2, 0)):
                         qubits = None
                     pm = PassManager(
                         [
-                            DynamicalDecoupling(
+                            ALAPScheduleAnalysis(durations),
+                            PadDynamicalDecoupling(
                                 durations, dd_sequence, qubits=qubits, spacing=spacings[j]
-                            )
+                            ),
                         ]
                     )
                     circuits = pm.run(circuits)
diff --git a/test/code_circuits/test_rep_codes.py b/test/code_circuits/test_rep_codes.py
index 763fe70d..6a643f62 100644
--- a/test/code_circuits/test_rep_codes.py
+++ b/test/code_circuits/test_rep_codes.py
@@ -20,8 +20,9 @@
 import itertools
 from random import choices
 
-from qiskit import Aer, QuantumCircuit, execute
+from qiskit import QuantumCircuit, execute
 from qiskit.providers.fake_provider import FakeJakarta
+from qiskit_aer import Aer, AerSimulator
 from qiskit_aer.noise import NoiseModel
 from qiskit_aer.noise.errors import depolarizing_error
 from qiskit_qec.circuits.repetition_code import RepetitionCodeCircuit as RepetitionCode
@@ -352,7 +353,7 @@ def test_single_error_202s(self):
                                 else:
                                     error_qc.x(code.link_qubit[code.link_index[q]])
                         error_qc.append(gate)
-                    counts = Aer.get_backend("qasm_simulator").run(error_qc).result().get_counts()
+                    counts = AerSimulator().run(error_qc).result().get_counts()
                     for string in counts:
                         # look at only bulk non-conjugate nodes
                         nodes = [
@@ -391,7 +392,7 @@ def test_feedforward(self):
             for gate in qc:
                 test_qc.append(gate)
             test_qcs.append(test_qc)
-        result = Aer.get_backend("qasm_simulator").run(test_qcs).result()
+        result = AerSimulator().run(test_qcs).result()
         # check result strings are correct
         for j in range(2):
             counts = result.get_counts(j)
diff --git a/test/heavy_hex_codes/test_heavy_hex_decoder.py b/test/heavy_hex_codes/test_heavy_hex_decoder.py
index 7d7a9da7..ed0a2909 100644
--- a/test/heavy_hex_codes/test_heavy_hex_decoder.py
+++ b/test/heavy_hex_codes/test_heavy_hex_decoder.py
@@ -1,7 +1,8 @@
 """Test a heavy-hexagon code decoder"""
 import unittest
 
-from qiskit import execute, Aer
+from qiskit import execute
+from qiskit_aer import Aer
 
 from qiskit_qec.codes.hhc import HHC
 from qiskit_qec.circuits.hhc_circuit import HHCCircuit
diff --git a/test/matching/test_circuitmatcher.py b/test/matching/test_circuitmatcher.py
index 61de1252..7c1393fa 100644
--- a/test/matching/test_circuitmatcher.py
+++ b/test/matching/test_circuitmatcher.py
@@ -1,7 +1,8 @@
 """Tests for the subsystem CSS circuit-level matching decoder."""
 import unittest
 
-from qiskit import execute, QuantumCircuit, Aer
+from qiskit import execute, QuantumCircuit
+from qiskit_aer import Aer
 
 from qiskit_qec.analysis.faultenumerator import FaultEnumerator
 from qiskit_qec.decoders.circuit_matching_decoder import temp_syndrome
diff --git a/test/matching/test_repetitionmatcher.py b/test/matching/test_repetitionmatcher.py
index 0f0642e9..52c666b6 100644
--- a/test/matching/test_repetitionmatcher.py
+++ b/test/matching/test_repetitionmatcher.py
@@ -1,7 +1,8 @@
 """Tests for the subsystem CSS circuit-level matching decoder."""
 import unittest
 
-from qiskit import execute, Aer
+from qiskit import execute
+from qiskit_aer import Aer
 
 from qiskit_qec.analysis.faultenumerator import FaultEnumerator
 from qiskit_qec.decoders.circuit_matching_decoder import temp_syndrome