diff --git a/.github/workflows/build-rtc.yml b/.github/workflows/build-rtc.yml
index 1310faab..a89676ba 100644
--- a/.github/workflows/build-rtc.yml
+++ b/.github/workflows/build-rtc.yml
@@ -135,7 +135,8 @@ jobs:
       matrix:
         include:
           # Linux x86_64 tests
-          - os: ubuntu-latest
+          # setup-python has no Python 3.9 build for Ubuntu 26.04 (ubuntu-latest).
+          - os: ubuntu-24.04
             python-version: "3.9"
             artifact: rtc-release-ubuntu-latest
           - os: ubuntu-latest
diff --git a/.github/workflows/test-api.yml b/.github/workflows/test-api.yml
index e16fd83b..c3be3268 100644
--- a/.github/workflows/test-api.yml
+++ b/.github/workflows/test-api.yml
@@ -26,7 +26,8 @@ on:
 jobs:
   failover:
     name: API (Python ${{ matrix.python-version }})
-    runs-on: ubuntu-latest
+    # setup-python has no Python 3.9 build for Ubuntu 26.04 (ubuntu-latest).
+    runs-on: ${{ matrix.python-version == '3.9' && 'ubuntu-24.04' || 'ubuntu-latest' }}
     strategy:
       fail-fast: false
       matrix: