diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 05d0be4f3..64512b858 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -1,8 +1,12 @@
 name: Run tests
 
 on:
-  - push
-  - pull_request
+  push:
+    branches:
+      - 'master'
+      - 'release-'
+    tags: '*'
+  pull_request:
 
 concurrency:
   # group by workflow and ref; the last slightly strange component ensures that for pull