diff --git a/infra/build/functions/trial_build.py b/infra/build/functions/trial_build.py
index e9e586483..8ec49f6e5 100644
--- a/infra/build/functions/trial_build.py
+++ b/infra/build/functions/trial_build.py
@@ -196,7 +196,7 @@ def _do_build_type_builds(args, config, credentials, build_type, projects):
           steps,
           credentials,
           build_type.type_name,
-          extra_tags=['trial-build']))
+          extra_tags=['trial-build', f'branch-{args.branch}']))
     except Exception:  # pylint: disable=broad-except
       # Handle flake.
       print('Failed to start build', project_name)