diff --git a/src/jaxsim/terrain/terrain.py b/src/jaxsim/terrain/terrain.py
index df0a0a402..c1f44081e 100644
--- a/src/jaxsim/terrain/terrain.py
+++ b/src/jaxsim/terrain/terrain.py
@@ -59,6 +59,10 @@ def build(plane_normal: list) -> "PlaneTerrain":
         Returns:
             PlaneTerrain: A PlaneTerrain instance.
         """
+        if not isinstance(plane_normal, list):
+            raise TypeError(
+                f"Expected a list for the plane normal vector, got: {type(plane_normal)}."
+            )
 
         return PlaneTerrain(plane_normal=plane_normal)