diff --git a/csbschema/validators.py b/csbschema/validators.py
index e82a219..7fb6200 100644
--- a/csbschema/validators.py
+++ b/csbschema/validators.py
@@ -407,6 +407,14 @@ def validate_b12_3_1_0_properties(document: dict, errors: List) -> None:
     if 'platform' not in properties:
         return
 
+    if 'trustedNode' not in properties:
+        return
+
+    if 'uniqueVesselID' not in properties['trustedNode']:
+        errors.append(_error_factory('/properties/trustedNode',
+                                     "'uniqueVesselID' is a required property."))
+        return
+
     validate_b12_3_1_0_platform(properties, errors)
 
 
diff --git a/tests/integration/validate_cmd.sh b/tests/integration/validate_cmd.sh
index 896b646..742ca43 100644
--- a/tests/integration/validate_cmd.sh
+++ b/tests/integration/validate_cmd.sh
@@ -58,6 +58,9 @@ csbschema validate -f docs/IHO/b12_v3_1_0_xyz_example-invalid.json \
   --version XYZ-3.1.0-2023-08
 check_failed_as_expected
 
+# Run valid B12 3.0.0 against B12 3.1.0 - should fail (but clean)
+csbschema validate -f docs/NOAA/noaa_b12_v3_0_0_required.json --version 3.1.0-2024-04
+check_failed_as_expected
 
 # Validate B12 3.2.0-BETA
 csbschema validate -f docs/IHO/b12_v3_2_0-BETA_example.json --version 3.2.0-BETA || exit $?
diff --git a/tests/unit/test_validators_current.py b/tests/unit/test_validators_current.py
index 13d34ec..cb12f8f 100644
--- a/tests/unit/test_validators_current.py
+++ b/tests/unit/test_validators_current.py
@@ -326,6 +326,13 @@ def test_validate_b12_3_2_0_BETA_valid(self):
         with self.assertRaises(KeyError):
             _: dict = result['errors']
 
+    def test_validate_b12_3_1_0_invalid_previous_version(self):
+        b12_filepath_invalid = Path(self.fixtures_dir, 'NOAA',
+                                    'noaa_b12_v3_0_0_required.json')
+        (valid, result) = validate_b12_3_1_0_2024_04(b12_filepath_invalid)
+        self.assertFalse(valid)
+        self.assertTrue(isinstance(result, dict))
+
 
 if __name__ == '__main__':
     unittest.main(