diff --git a/codegen/smithy-aws-go-codegen/src/main/resources/software/amazon/smithy/aws/go/codegen/endpoints.json b/codegen/smithy-aws-go-codegen/src/main/resources/software/amazon/smithy/aws/go/codegen/endpoints.json
index eb50706f93b..73b271303c8 100644
--- a/codegen/smithy-aws-go-codegen/src/main/resources/software/amazon/smithy/aws/go/codegen/endpoints.json
+++ b/codegen/smithy-aws-go-codegen/src/main/resources/software/amazon/smithy/aws/go/codegen/endpoints.json
@@ -21,7 +21,7 @@
     "dnsSuffix" : "amazonaws.com",
     "partition" : "aws",
     "partitionName" : "AWS Standard",
-    "regionRegex" : "^(us|eu|ap|sa|ca|me|af|il)\\-\\w+\\-\\d+$",
+    "regionRegex" : "^(us|eu|ap|sa|ca|me|af|il|mx)\\-\\w+\\-\\d+$",
     "regions" : {
       "af-south-1" : {
         "description" : "Africa (Cape Town)"