diff --git a/.github/workflows/commcare-android-pr-workflow.yml b/.github/workflows/commcare-android-pr-workflow.yml
index c8ecb132d2..81bf84dcfd 100644
--- a/.github/workflows/commcare-android-pr-workflow.yml
+++ b/.github/workflows/commcare-android-pr-workflow.yml
@@ -22,7 +22,9 @@ concurrency:
 jobs:
   build-test-assemble:
     name: Build
-    runs-on: ubuntu-latest
+    # Pinned until dimagi/mobile-deploy's cross-request script supports Python 3.10+;
+    # setup-python has no Python 3.9 build for Ubuntu 26.04.
+    runs-on: ubuntu-24.04
     permissions:
       contents: read
       pull-requests: write
@@ -36,7 +38,7 @@ jobs:
         if: ${{ github.event_name == 'pull_request' }}
         uses: actions/setup-python@v6
         with:
-          python-version: '3.12'
+          python-version: '3.9'
       - name: Download cross request script
         if: ${{ github.event_name == 'pull_request' }}
         run: |