diff --git a/.github/workflows/1_create_release_pr.yml b/.github/workflows/1_create_release_pr.yml
index 6eeec9cb..b56daf47 100644
--- a/.github/workflows/1_create_release_pr.yml
+++ b/.github/workflows/1_create_release_pr.yml
@@ -20,7 +20,7 @@ jobs:
         uses: cylc/release-actions/stage-1/sanitize-inputs@v1
 
       - name: Checkout repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           ref: ${{ env.BASE_REF }}
           fetch-depth: 0  # need to fetch all commits to check contributors
diff --git a/.github/workflows/2_auto_publish_release.yml b/.github/workflows/2_auto_publish_release.yml
index 10e0bf2f..73d17598 100644
--- a/.github/workflows/2_auto_publish_release.yml
+++ b/.github/workflows/2_auto_publish_release.yml
@@ -22,7 +22,7 @@ jobs:
     steps:
 
     - name: Checkout repo
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         ref: ${{ env.MERGE_SHA }}
 
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 651ffd94..ac046d80 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -35,7 +35,7 @@ jobs:
         python: ['3.12', '3']  # oldest/newest supported versions
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Python
         uses: mamba-org/setup-micromamba@v2
diff --git a/.github/workflows/shortlog.yml b/.github/workflows/shortlog.yml
index 090426f6..24463380 100644
--- a/.github/workflows/shortlog.yml
+++ b/.github/workflows/shortlog.yml
@@ -16,7 +16,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: Checkout repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0  # need to fetch all commits to check contributors
 
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 35aa7ede..0d3c44d0 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -36,7 +36,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Patch DNS
         uses: cylc/release-actions/patch-dns@v1
@@ -94,7 +94,7 @@ jobs:
     timeout-minutes: 2
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Download coverage artifacts
         uses: actions/download-artifact@v6
diff --git a/.github/workflows/update_copyright.yml b/.github/workflows/update_copyright.yml
index c6d490f2..d0f8d04c 100644
--- a/.github/workflows/update_copyright.yml
+++ b/.github/workflows/update_copyright.yml
@@ -29,7 +29,7 @@ jobs:
     steps:
 
       - name: Checkout repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Configure git
         uses: cylc/release-actions/configure-git@v1
diff --git a/.github/workflows/update_ui.yml b/.github/workflows/update_ui.yml
index 412c6b15..ee27ce89 100644
--- a/.github/workflows/update_ui.yml
+++ b/.github/workflows/update_ui.yml
@@ -22,7 +22,7 @@ jobs:
       HEAD_BRANCH: update-ui-${{ github.run_number }}
     steps:
       - name: checkout cylc-uiserver
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           ref: ${{ inputs.base-branch }}