diff --git a/source/isaaclab_tasks/changelog.d/default-newton-locomotion.minor.rst b/source/isaaclab_tasks/changelog.d/default-newton-locomotion.minor.rst
new file mode 100644
index 000000000000..2b43b7ed0a7d
--- /dev/null
+++ b/source/isaaclab_tasks/changelog.d/default-newton-locomotion.minor.rst
@@ -0,0 +1,5 @@
+Changed
+^^^^^^^
+
+* **Breaking:** Changed the Ant, Humanoid, and Velocity task families to use
+  Newton MJWarp by default. Pass an explicit physics preset to retain Isaac Sim PhysX.
diff --git a/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/ant/ant_direct_env_cfg.py b/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/ant/ant_direct_env_cfg.py
index a7f0c1d1e42d..38bc104d929d 100644
--- a/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/ant/ant_direct_env_cfg.py
+++ b/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/ant/ant_direct_env_cfg.py
@@ -33,7 +33,6 @@ class AntPhysicsCfg(PresetCfg):
     isaacsim_physx: PhysxCfg = PhysxCfg(bounce_threshold_velocity=0.2)
     ovphysx: OvPhysxCfg = OvPhysxCfg()
     physx: PhysxAutoCfg = PhysxAutoCfg(isaacsim_physx=isaacsim_physx, ovphysx=ovphysx)
-    default = isaacsim_physx
     newton_mjwarp: NewtonCfg = NewtonCfg(
         solver_cfg=MJWarpSolverCfg(
             njmax=45,
@@ -50,6 +49,7 @@ class AntPhysicsCfg(PresetCfg):
         debug_mode=False,
         use_cuda_graph=True,
     )
+    default = newton_mjwarp
 
 
 @configclass
diff --git a/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/ant/ant_manager_env_cfg.py b/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/ant/ant_manager_env_cfg.py
index bfdc93912e6a..d628496cf9a3 100644
--- a/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/ant/ant_manager_env_cfg.py
+++ b/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/ant/ant_manager_env_cfg.py
@@ -37,7 +37,6 @@ class AntPhysicsCfg(PresetCfg):
     isaacsim_physx: PhysxCfg = PhysxCfg(bounce_threshold_velocity=0.2)
     ovphysx: OvPhysxCfg = OvPhysxCfg()
     physx: PhysxAutoCfg = PhysxAutoCfg(isaacsim_physx=isaacsim_physx, ovphysx=ovphysx)
-    default: PhysxCfg = isaacsim_physx
     newton_mjwarp: NewtonCfg = NewtonCfg(
         solver_cfg=MJWarpSolverCfg(
             njmax=45,
@@ -54,6 +53,7 @@ class AntPhysicsCfg(PresetCfg):
         debug_mode=False,
         use_cuda_graph=True,
     )
+    default: NewtonCfg = newton_mjwarp
 
 
 @configclass
@@ -143,8 +143,8 @@ def __post_init__(self):
 class AntObservationsCfg(PresetCfg):
     physx: ObservationsCfg = ObservationsCfg()
     isaacsim_physx: ObservationsCfg = physx
-    default: ObservationsCfg = isaacsim_physx
     newton_mjwarp: ObservationsCfg = ObservationsCfg()
+    default: ObservationsCfg = newton_mjwarp
 
 
 @configclass
diff --git a/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/humanoid/humanoid_direct_env_cfg.py b/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/humanoid/humanoid_direct_env_cfg.py
index bc0929b86d1e..8fbb51b1c950 100644
--- a/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/humanoid/humanoid_direct_env_cfg.py
+++ b/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/humanoid/humanoid_direct_env_cfg.py
@@ -29,7 +29,6 @@ class HumanoidPhysicsCfg(PresetCfg):
     isaacsim_physx: PhysxCfg = PhysxCfg(bounce_threshold_velocity=0.2)
     ovphysx: OvPhysxCfg = OvPhysxCfg()
     physx: PhysxAutoCfg = PhysxAutoCfg(isaacsim_physx=isaacsim_physx, ovphysx=ovphysx)
-    default = isaacsim_physx
     newton_mjwarp: NewtonCfg = NewtonCfg(
         solver_cfg=MJWarpSolverCfg(
             njmax=80,
@@ -42,6 +41,7 @@ class HumanoidPhysicsCfg(PresetCfg):
         num_substeps=2,
         debug_mode=False,
     )
+    default = newton_mjwarp
 
 
 @configclass
diff --git a/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/humanoid/humanoid_manager_env_cfg.py b/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/humanoid/humanoid_manager_env_cfg.py
index d47422c1ad9a..11a3aa6f16f6 100644
--- a/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/humanoid/humanoid_manager_env_cfg.py
+++ b/source/isaaclab_tasks/isaaclab_tasks/core/locomotion/humanoid/humanoid_manager_env_cfg.py
@@ -49,7 +49,6 @@ class HumanoidPhysicsCfg(PresetCfg):
     isaacsim_physx: PhysxCfg = PhysxCfg(bounce_threshold_velocity=0.2)
     ovphysx: OvPhysxCfg = OvPhysxCfg()
     physx: PhysxAutoCfg = PhysxAutoCfg(isaacsim_physx=isaacsim_physx, ovphysx=ovphysx)
-    default: PhysxCfg = isaacsim_physx
     newton_mjwarp: NewtonCfg = NewtonCfg(
         solver_cfg=MJWarpSolverCfg(
             njmax=80,
@@ -62,6 +61,7 @@ class HumanoidPhysicsCfg(PresetCfg):
         num_substeps=2,
         debug_mode=False,
     )
+    default: NewtonCfg = newton_mjwarp
 
 
 ##
@@ -147,8 +147,8 @@ def __post_init__(self):
 class HumanoidObservationsCfg(PresetCfg):
     physx: ObservationsCfg = ObservationsCfg()
     isaacsim_physx: ObservationsCfg = physx
-    default: ObservationsCfg = isaacsim_physx
     newton_mjwarp: ObservationsCfg = ObservationsCfg()
+    default: ObservationsCfg = newton_mjwarp
 
 
 @configclass
diff --git a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/anymal_d/flat_env_cfg.py b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/anymal_d/flat_env_cfg.py
index 8b6465f7b449..f2b96e28d0b5 100644
--- a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/anymal_d/flat_env_cfg.py
+++ b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/anymal_d/flat_env_cfg.py
@@ -32,7 +32,7 @@ class PhysicsCfg(PresetCfg):
         debug_mode=False,
     )
     newton_kamino = NewtonCfg(solver_cfg=KaminoPADMMSolverCfg(max_contacts_per_world=64))
-    default = isaacsim_physx
+    default = newton_mjwarp
 
 
 @configclass
diff --git a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/cassie/flat_env_cfg.py b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/cassie/flat_env_cfg.py
index 1cf5501abfe1..21ba95740cdb 100644
--- a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/cassie/flat_env_cfg.py
+++ b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/cassie/flat_env_cfg.py
@@ -33,7 +33,7 @@ class PhysicsCfg(PresetCfg):
         debug_mode=False,
     )
     newton_kamino = NewtonCfg(solver_cfg=KaminoPADMMSolverCfg(max_contacts_per_world=64))
-    default = isaacsim_physx
+    default = newton_mjwarp
 
 
 @configclass
diff --git a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/g1/flat_env_cfg.py b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/g1/flat_env_cfg.py
index b40e021d6103..5a53be0c3ee3 100644
--- a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/g1/flat_env_cfg.py
+++ b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/g1/flat_env_cfg.py
@@ -34,7 +34,7 @@ class PhysicsCfg(PresetCfg):
         debug_mode=False,
     )
     newton_kamino = NewtonCfg(solver_cfg=KaminoPADMMSolverCfg(max_contacts_per_world=64))
-    default = isaacsim_physx
+    default = newton_mjwarp
 
 
 @configclass
diff --git a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/go2/flat_env_cfg.py b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/go2/flat_env_cfg.py
index b40781cba880..bcb90551d801 100644
--- a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/go2/flat_env_cfg.py
+++ b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/go2/flat_env_cfg.py
@@ -33,7 +33,7 @@ class PhysicsCfg(PresetCfg):
         debug_mode=False,
     )
     newton_kamino = NewtonCfg(solver_cfg=KaminoPADMMSolverCfg(max_contacts_per_world=64))
-    default = isaacsim_physx
+    default = newton_mjwarp
 
 
 @configclass
diff --git a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/h1/flat_env_cfg.py b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/h1/flat_env_cfg.py
index 33b128a80632..1e77fdb16f3f 100644
--- a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/h1/flat_env_cfg.py
+++ b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/config/h1/flat_env_cfg.py
@@ -33,7 +33,7 @@ class PhysicsCfg(PresetCfg):
         debug_mode=False,
     )
     newton_kamino = NewtonCfg(solver_cfg=KaminoPADMMSolverCfg(max_contacts_per_world=64))
-    default = isaacsim_physx
+    default = newton_mjwarp
 
 
 @configclass
diff --git a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/velocity_env_cfg.py b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/velocity_env_cfg.py
index 446f170d9bb4..2f260dbccf2b 100644
--- a/source/isaaclab_tasks/isaaclab_tasks/core/velocity/velocity_env_cfg.py
+++ b/source/isaaclab_tasks/isaaclab_tasks/core/velocity/velocity_env_cfg.py
@@ -64,7 +64,7 @@ class RoughPhysicsCfg(PresetCfg):
         debug_mode=False,
         default_shape_cfg=NewtonShapeCfg(margin=0.0, ke=160000.0, kd=1100.0),
     )
-    default = isaacsim_physx
+    default = newton_mjwarp
 
 
 ##
diff --git a/source/isaaclab_tasks/test/core/test_environment_determinism.py b/source/isaaclab_tasks/test/core/test_environment_determinism.py
index 74c558fcd1ae..5f6b7867a1e2 100644
--- a/source/isaaclab_tasks/test/core/test_environment_determinism.py
+++ b/source/isaaclab_tasks/test/core/test_environment_determinism.py
@@ -57,8 +57,8 @@ def test_manipulation_env_determinism(task_name, device):
 )
 @pytest.mark.parametrize("device", ["cuda", "cpu"])
 def test_locomotion_env_determinism(task_name, device):
-    """Check deterministic environment creation for locomotion."""
-    _test_environment_determinism(task_name, device)
+    """Check deterministic Isaac Sim PhysX environment creation for locomotion."""
+    _test_environment_determinism(task_name, device, physics_preset_name="isaacsim_physx")
 
 
 @pytest.mark.parametrize(
diff --git a/source/isaaclab_visualizers/changelog.d/default-newton-locomotion.skip b/source/isaaclab_visualizers/changelog.d/default-newton-locomotion.skip
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/source/isaaclab_visualizers/test/visualizer_golden_utils.py b/source/isaaclab_visualizers/test/visualizer_golden_utils.py
index 0c454f0903fe..e7cc7e70a420 100644
--- a/source/isaaclab_visualizers/test/visualizer_golden_utils.py
+++ b/source/isaaclab_visualizers/test/visualizer_golden_utils.py
@@ -54,6 +54,9 @@
     # AnymalD: golden captured warm, first attempt runs cold; observed up to 9.61%.
     "anymal_d-kit-tiled": 12.0,
     "anymal_d-kit-viewport": 4.5,
+    # Newton GL tiled output differs by 0.64% between the L40S CI runner and the golden.
+    # Keep this narrow 1.0% tolerance paired with an SSIM guard for scene regressions.
+    "anymal_d-newton-tiled": 1.0,
     # RTX PRO 6000 Blackwell differs by up to 6.5% while preserving the expected pose.
     "shadow_hand-kit-tiled": 7.0,
     "shadow_hand-kit-viewport": 2.0,
@@ -78,6 +81,9 @@
     # 0.910 lets attempt 1 pass with a large gap above wrong-pose regressions (~0.69).
     "anymal_d-kit-tiled": 0.910,
     "anymal_d-kit-viewport": 0.960,
+    # The L40S comparison reaches SSIM 0.9883; retain a structural threshold well above
+    # known pose regressions while accepting this cross-GPU rasterization variation.
+    "anymal_d-newton-tiled": 0.980,
     # Cross-GPU RTX variation; observed SSIM 0.941 on RTX PRO 6000 Blackwell vs L40S goldens.
     # Wrong-pose regressions drop SSIM below 0.90.
     "shadow_hand-kit-tiled": 0.935,
diff --git a/source/isaaclab_visualizers/test/visualizer_integration_utils.py b/source/isaaclab_visualizers/test/visualizer_integration_utils.py
index 51fb39088096..2b4a46c6c587 100644
--- a/source/isaaclab_visualizers/test/visualizer_integration_utils.py
+++ b/source/isaaclab_visualizers/test/visualizer_integration_utils.py
@@ -1606,8 +1606,7 @@ def _make_anymal_d_env(visualizer_kind: str | tuple[str, ...], backend_kind: str
     from isaaclab.envs import ManagerBasedRLEnv
 
     env_cfg = copy.deepcopy(AnymalDFlatEnvCfg())
-    preset_key = "newton_mjwarp" if backend_kind == "newton" else "default"
-    env_cfg.sim.physics = getattr(env_cfg.sim.physics, preset_key)
+    env_cfg = _apply_env_cfg_preset(env_cfg, "newton_mjwarp" if backend_kind == "newton" else "physx")
     env_cfg.scene.num_envs = (
         _ANYMAL_D_TILED_CAMERA_INTEGRATION_NUM_ENVS if tiled_camera else _ANYMAL_D_INTEGRATION_NUM_ENVS
     )