diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index bc9c33ce..5aa7d61b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -10,6 +10,7 @@ on:
 env:
   CARGO_TERM_COLOR: always
   CMAKE_CONFIG: RelWithDebInfo
+  UV_VERSION: "0.9.0"
 
 jobs:
   rustfmt:
@@ -224,7 +225,7 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y --no-upgrade doxygen
           pipx install uv
-          uv sync
+          uv sync --locked
         if: runner.os == 'Linux'
 
       - name: Install packages for building docs (Windows)
@@ -243,12 +244,12 @@ jobs:
           echo "${{ github.workspace }}\doxygen-1.13.2.windows.x64.bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
 
           pipx install uv
-          uv sync
+          uv sync --locked
         if: runner.os == 'Windows'
 
       - name: Build docs
         working-directory: docs
-        run: uv run -- sphinx-build -b html . build/html
+        run: uv run --locked -- sphinx-build -b html . build/html
 
       - name: Package the C++ wrapper
         working-directory: cpp/build
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 10873f54..bc3f4ba0 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -97,11 +97,11 @@ jobs:
           echo "${{ github.workspace }}\doxygen-1.13.2.windows.x64.bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
 
           pipx install uv
-          uv sync
+          uv sync --locked
 
       - name: Build docs
         working-directory: docs
-        run: uv run -- sphinx-build -b html . build/html
+        run: uv run --locked -- sphinx-build -b html . build/html
 
       - name: Build archive
         id: build-archive