diff --git a/flow360/component/simulation/meshing_param/snappy/snappy_mesh_refinements.py b/flow360/component/simulation/meshing_param/snappy/snappy_mesh_refinements.py
index 0beed13d3..34645afdd 100644
--- a/flow360/component/simulation/meshing_param/snappy/snappy_mesh_refinements.py
+++ b/flow360/component/simulation/meshing_param/snappy/snappy_mesh_refinements.py
@@ -12,7 +12,6 @@
 from flow360.component.simulation.meshing_param.volume_params import UniformRefinement
 from flow360.component.simulation.primitives import SnappyBody, Surface
 from flow360.component.simulation.unit_system import AngleType, LengthType
-from flow360.log import log
 
 
 class SnappyEntityRefinement(Flow360BaseModel, metaclass=ABCMeta):
@@ -36,11 +35,10 @@ def _check_spacing_order(self) -> Self:
     def _check_proximity_spacing(self) -> Self:
         if self.min_spacing and self.proximity_spacing:
             if self.proximity_spacing > self.min_spacing:
-                log.warning(
-                    f"Proximity spacing ({self.proximity_spacing}) was set higher than the minimal spacing"
-                    + f"({self.min_spacing}), setting proximity spacing to minimal spacing."
+                raise ValueError(
+                    f"Proximity spacing ({self.proximity_spacing}) was set higher than the minimal spacing "
+                    + f"({self.min_spacing})."
                 )
-                self.proximity_spacing = self.min_spacing
         return self
 
 
diff --git a/flow360/component/simulation/meshing_param/snappy/snappy_params.py b/flow360/component/simulation/meshing_param/snappy/snappy_params.py
index b5f1097ca..44328b81d 100644
--- a/flow360/component/simulation/meshing_param/snappy/snappy_params.py
+++ b/flow360/component/simulation/meshing_param/snappy/snappy_params.py
@@ -56,8 +56,16 @@ def _check_body_refinements_w_defaults(self):
             return self
         for refinement in self.refinements:
             if isinstance(refinement, BodyRefinement):
+                if refinement.min_spacing is None and refinement.proximity_spacing:
+                    if refinement.proximity_spacing > self.defaults.min_spacing:
+                        raise ValueError(
+                            f"Proximity spacing for a BodyRefinement ({refinement.proximity_spacing}) was set higher "
+                            + f"than the minimal spacing ({self.defaults.min_spacing})."
+                        )
+
                 if refinement.min_spacing is None and refinement.max_spacing is None:
                     continue
+
                 if refinement.min_spacing is None and self.defaults.min_spacing.to(
                     "m"
                 ) > refinement.max_spacing.to("m"):
diff --git a/tests/simulation/params/meshing_validation/test_refinements_validation.py b/tests/simulation/params/meshing_validation/test_refinements_validation.py
index 13fcfda77..fe5df3001 100644
--- a/tests/simulation/params/meshing_validation/test_refinements_validation.py
+++ b/tests/simulation/params/meshing_validation/test_refinements_validation.py
@@ -207,3 +207,74 @@ def test_snappy_body_refinement_validator():
     snappy.BodyRefinement(
         bodies=SnappyBody(name="body1", surfaces=[Surface(name="surface")]), gap_resolution=2 * u.mm
     )
+
+
+def test_snappy_proximity_spacing_error_when_exceeds_default_min_spacing():
+    """When min_spacing is not set on a BodyRefinement but proximity_spacing exceeds
+    defaults.min_spacing, a ValueError should be raised."""
+    message = "Proximity spacing for a BodyRefinement (5.0 mm) was set higher than the minimal spacing (3.0 mm)."
+    with SI_unit_system, pytest.raises(pd.ValidationError, match=re.escape(message)):
+        snappy.SurfaceMeshingParams(
+            defaults=snappy.SurfaceMeshingDefaults(
+                min_spacing=3 * u.mm, max_spacing=10 * u.mm, gap_resolution=0.1 * u.mm
+            ),
+            refinements=[
+                snappy.BodyRefinement(
+                    bodies=SnappyBody(name="body1", surfaces=[Surface(name="surface")]),
+                    proximity_spacing=5 * u.mm,
+                    max_spacing=10 * u.mm,
+                ),
+            ],
+        )
+
+
+def test_snappy_proximity_spacing_ok_when_below_default_min_spacing():
+    """When proximity_spacing is already <= defaults.min_spacing, no error should be raised."""
+    with SI_unit_system:
+        body = SnappyBody(name="body1", surfaces=[Surface(name="surface")])
+        params = snappy.SurfaceMeshingParams(
+            defaults=snappy.SurfaceMeshingDefaults(
+                min_spacing=3 * u.mm, max_spacing=10 * u.mm, gap_resolution=0.1 * u.mm
+            ),
+            refinements=[
+                snappy.BodyRefinement(
+                    bodies=body,
+                    proximity_spacing=2 * u.mm,
+                    max_spacing=10 * u.mm,
+                ),
+            ],
+        )
+        assert params.refinements[0].proximity_spacing == 2 * u.mm
+
+
+def test_snappy_proximity_spacing_error_with_explicit_min_spacing():
+    """When both min_spacing and proximity_spacing are set on the refinement
+    and proximity_spacing > min_spacing, the entity-level validator raises."""
+    message = "Proximity spacing (6.0 mm) was set higher than the minimal spacing (4.0 mm)."
+    with SI_unit_system, pytest.raises(pd.ValidationError, match=re.escape(message)):
+        snappy.BodyRefinement(
+            bodies=SnappyBody(name="body1", surfaces=[Surface(name="surface")]),
+            min_spacing=4 * u.mm,
+            proximity_spacing=6 * u.mm,
+            max_spacing=10 * u.mm,
+        )
+
+
+def test_snappy_proximity_spacing_ok_when_min_spacing_is_set():
+    """When min_spacing is explicitly set and proximity_spacing <= min_spacing, no error."""
+    with SI_unit_system:
+        body = SnappyBody(name="body1", surfaces=[Surface(name="surface")])
+        params = snappy.SurfaceMeshingParams(
+            defaults=snappy.SurfaceMeshingDefaults(
+                min_spacing=1 * u.mm, max_spacing=10 * u.mm, gap_resolution=0.1 * u.mm
+            ),
+            refinements=[
+                snappy.BodyRefinement(
+                    bodies=body,
+                    min_spacing=4 * u.mm,
+                    proximity_spacing=3 * u.mm,
+                    max_spacing=10 * u.mm,
+                ),
+            ],
+        )
+        assert params.refinements[0].proximity_spacing == 3 * u.mm