diff --git a/.github/workflows/build-binaries.yml b/.github/workflows/build-binaries.yml
index 7186238d6..b585e3bf8 100644
--- a/.github/workflows/build-binaries.yml
+++ b/.github/workflows/build-binaries.yml
@@ -44,7 +44,7 @@ jobs:
         with:
           workspaces: temporalio/bridge -> target
       - uses: astral-sh/setup-uv@v5
-      - run: uv sync --all-extras
+      - run: uv sync --all-extras --python 3.13
 
       # Add the source dist only for Linux x64 for now
       - if: ${{ matrix.package-suffix == 'linux-amd64' }}
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2b079e60b..473c42bec 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -48,7 +48,20 @@ jobs:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
       - uses: astral-sh/setup-uv@v5
       - run: uv tool install poethepoet
-      - run: uv sync --all-extras
+      - run: uv sync --all-extras --python ${{ matrix.python }}
+      - name: Check python version
+        shell: bash
+        run: |
+          actual=$(uv run python -c "import sys; print('.'.join(map(str, sys.version_info[:2])))")
+          if [[ "$actual" != "${{ matrix.python }}" ]]; then
+            echo "Python version in use by uv ($actual) does not match intended version (${{ matrix.python }})"
+            exit 1
+          fi
+          actual=$(python -c "import sys; print('.'.join(map(str, sys.version_info[:2])))")
+          if [[ "$actual" != "${{ matrix.python }}" ]]; then
+            echo "Python version on PATH ($actual) does not match intended version (${{ matrix.python }})"
+            exit 1
+          fi
       - run: poe bridge-lint
         if: ${{ matrix.clippyLinter }}
       - run: poe lint
@@ -84,7 +97,7 @@ jobs:
           TEMPORAL_TEST_PROTO3: 1
         run: |
           uv add --python 3.9 "protobuf<4"
-          uv sync --all-extras
+          uv sync --all-extras --python 3.9
           poe build-develop
           poe gen-protos
           poe format
diff --git a/.github/workflows/run-bench.yml b/.github/workflows/run-bench.yml
index 6dcad63e8..d08c98e93 100644
--- a/.github/workflows/run-bench.yml
+++ b/.github/workflows/run-bench.yml
@@ -47,7 +47,7 @@ jobs:
       - uses: astral-sh/setup-uv@v5
       # Build
       - run: uv tool install poethepoet
-      - run: uv sync --all-extras
+      - run: uv sync --all-extras --python 3.13
       - run: poe build-develop-with-release
       
       # Run a bunch of bench tests. We run multiple times since results vary.
diff --git a/README.md b/README.md
index 58e775da1..1983ed982 100644
--- a/README.md
+++ b/README.md
@@ -1544,7 +1544,7 @@ poe test -s --log-cli-level=DEBUG -k test_sync_activity_thread_cancel_caught
 #### Proto Generation and Testing
 
 To allow for backwards compatibility, protobuf code is generated on the 3.x series of the protobuf library. To generate
-protobuf code, you must be on Python <= 3.10, and then run `uv add "protobuf<4"` + `uv sync --all-extras`. Then the
+protobuf code, run `uv add "protobuf<4" --python 3.10` + `uv sync --all-extras --python 3.10`. Then the
 protobuf files can be generated via `poe gen-protos`. Tests can be run for protobuf version 3 by setting the
 `TEMPORAL_TEST_PROTO3` env var to `1` prior to running tests.