diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index cfd126b..315658f 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -9,7 +9,7 @@ permissions:
 jobs:
   build_cached:
     name: Build tart (cached)
-    runs-on: ghcr.io/cirruslabs/macos-runner:tahoe
+    runs-on: macos-26
     timeout-minutes: 30
     steps:
       - uses: actions/checkout@v5
@@ -29,7 +29,7 @@ jobs:
 
   build_no_cache:
     name: Build tart (no cache)
-    runs-on: ghcr.io/cirruslabs/macos-runner:tahoe
+    runs-on: macos-26
     timeout-minutes: 30
     steps:
       - uses: actions/checkout@v5
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index e38ac4d..3f04444 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -13,7 +13,7 @@ jobs:
   release:
     if: github.event_name == 'push' && github.repository == 'openai/tart'
     name: Release
-    runs-on: macos-latest
+    runs-on: macos-26
     environment: publish
     timeout-minutes: 90
     permissions:
@@ -84,7 +84,7 @@ jobs:
   snapshot:
     if: github.event_name == 'workflow_dispatch'
     name: Release (Dry Run)
-    runs-on: macos-latest
+    runs-on: macos-26
     timeout-minutes: 90
     permissions:
       contents: read