diff --git a/.github/workflows/build-cpp-libs.yml b/.github/workflows/build-cpp-libs.yml
index eb79325..5d5ae42 100644
--- a/.github/workflows/build-cpp-libs.yml
+++ b/.github/workflows/build-cpp-libs.yml
@@ -34,7 +34,7 @@ jobs:
     steps:
 
       - name: checkout repo & submodules
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: install system packages
         run: |
diff --git a/.github/workflows/build-wheels.yml b/.github/workflows/build-wheels.yml
index 897c684..1eff854 100644
--- a/.github/workflows/build-wheels.yml
+++ b/.github/workflows/build-wheels.yml
@@ -60,7 +60,7 @@ jobs:
 
     steps:
       - name: checkout repo & submodules
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
 
diff --git a/.github/workflows/ctest-macos.yml b/.github/workflows/ctest-macos.yml
index d61fdf0..a54fc23 100644
--- a/.github/workflows/ctest-macos.yml
+++ b/.github/workflows/ctest-macos.yml
@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: checkout repo & submodules
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: install system packages
         run: brew install boost
diff --git a/.github/workflows/ctest-ubuntu.yml b/.github/workflows/ctest-ubuntu.yml
index 48090ce..388d125 100644
--- a/.github/workflows/ctest-ubuntu.yml
+++ b/.github/workflows/ctest-ubuntu.yml
@@ -15,7 +15,7 @@ jobs:
 
     steps:
       - name: checkout repo & submodules
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: install system packages
         run: |
diff --git a/.github/workflows/pytest-ubuntu.yml b/.github/workflows/pytest-ubuntu.yml
index 2c50c79..1d1949e 100644
--- a/.github/workflows/pytest-ubuntu.yml
+++ b/.github/workflows/pytest-ubuntu.yml
@@ -21,7 +21,7 @@ jobs:
     steps:
 
       - name: checkout repo & submodules
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
 
diff --git a/.github/workflows/regen-snapshot-data.yml b/.github/workflows/regen-snapshot-data.yml
index a8d459f..92572b8 100644
--- a/.github/workflows/regen-snapshot-data.yml
+++ b/.github/workflows/regen-snapshot-data.yml
@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout repo & submodules
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Set up Python
         uses: actions/setup-python@v6