diff --git a/.github/workflows/system-tests-pr.yml b/.github/workflows/system-tests-pr.yml
index 683b863b6..45111c3a6 100644
--- a/.github/workflows/system-tests-pr.yml
+++ b/.github/workflows/system-tests-pr.yml
@@ -7,6 +7,7 @@ on:
 jobs:
   gather-refs:
     name: Map Git branches to latest refs
+    if: github.event.label.name == 'trigger-system-tests'
     runs-on: ubuntu-latest
     outputs:
       ref-precice: ${{ steps.ref-precice.outputs.shorthash }}
diff --git a/changelog-entries/682.md b/changelog-entries/682.md
new file mode 100644
index 000000000..1c4d7d60f
--- /dev/null
+++ b/changelog-entries/682.md
@@ -0,0 +1 @@
+- Gate the `gather-refs` job in the System tests (PR) workflow on the `trigger-system-tests` label, so the workflow skips entirely for PRs labeled with anything else (e.g. "bug", "GSoC"), reducing GitHub API usage. #682