diff --git a/.github/workflows/mutation.yml b/.github/workflows/mutation.yml
index 4b06da0..a25e301 100644
--- a/.github/workflows/mutation.yml
+++ b/.github/workflows/mutation.yml
@@ -18,7 +18,9 @@ jobs:
   mutate:
     name: Mutation score
     runs-on: ubuntu-latest
-    timeout-minutes: 15
+    # Successful runs took 9-15 minutes (measured over the last 10, 2026-10-06), so 15 cut off
+    # four of them mid-run as cancellations. 30 leaves room without letting a hung run idle long.
+    timeout-minutes: 30
 
     steps:
       - name: Checkout