diff --git a/tests/test_litellm/llms/bedrock/test_base_aws_llm.py b/tests/test_litellm/llms/bedrock/test_base_aws_llm.py
index cf9fee6bacf..335f057edbb 100644
--- a/tests/test_litellm/llms/bedrock/test_base_aws_llm.py
+++ b/tests/test_litellm/llms/bedrock/test_base_aws_llm.py
@@ -548,9 +548,6 @@ def test_eks_irsa_ambient_credentials_used():
     """
     base_aws_llm = BaseAWSLLM()
     
-    # Mock the boto3 STS client
-    mock_sts_client = MagicMock()
-    
     # Mock the STS response with proper expiration handling
     mock_expiry = MagicMock()
     mock_expiry.tzinfo = timezone.utc
@@ -568,6 +565,9 @@ def test_eks_irsa_ambient_credentials_used():
             "Expiration": mock_expiry,
         }
     }
+    
+    # Case 1: only aws_role_name and aws_session_name (no aws_region_name)
+    mock_sts_client = MagicMock()
     mock_sts_client.assume_role.return_value = mock_sts_response
     
     with patch("boto3.client", return_value=mock_sts_client) as mock_boto3_client:
@@ -588,13 +588,31 @@ def test_eks_irsa_ambient_credentials_used():
         # Should call assume_role
         mock_sts_client.assume_role.assert_called_once_with(
             RoleArn="arn:aws:iam::2222222222222:role/LitellmEvalBedrockRole",
-            RoleSessionName="test-session"
+            RoleSessionName="test-session",
         )
         
         # Verify credentials are returned correctly
         assert credentials.access_key == "assumed-access-key"
-        assert credentials.secret_key == "assumed-secret-key"
-        assert credentials.token == "assumed-session-token"
+        assert ttl is not None
+
+    # Case 2: aws_role_name, aws_session_name, and aws_region_name (regional STS)
+    mock_sts_client2 = MagicMock()
+    mock_sts_client2.assume_role.return_value = mock_sts_response
+    with patch("boto3.client", return_value=mock_sts_client2) as mock_boto3_client:
+        credentials, ttl = base_aws_llm._auth_with_aws_role(
+            aws_access_key_id=None,
+            aws_secret_access_key=None,
+            aws_session_token=None,
+            aws_role_name="arn:aws:iam::2222222222222:role/LitellmEvalBedrockRole",
+            aws_session_name="test-session",
+            aws_region_name="us-east-1",
+        )
+        mock_boto3_client.assert_called_once_with("sts", region_name="us-east-1", verify=True)
+        mock_sts_client2.assume_role.assert_called_once_with(
+            RoleArn="arn:aws:iam::2222222222222:role/LitellmEvalBedrockRole",
+            RoleSessionName="test-session",
+        )
+        assert credentials.access_key == "assumed-access-key"
         assert ttl is not None