diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 92ba45b..2ae1138 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -3,12 +3,12 @@ on: [push, pull_request]
 jobs:
   test:
     name: Test
-    runs-on: macos-12
+    runs-on: macos-13
     # Prevent duplicate builds on internal PRs.
     if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
     strategy:
       matrix:
-        swift: ["5.8"]
+        swift: ["5.9"]
     steps:
       - uses: fwal/setup-swift@v1
         with: