diff --git a/.github/workflows/checkup.yaml b/.github/workflows/checkup.yaml
index 8d0ea01..b855268 100644
--- a/.github/workflows/checkup.yaml
+++ b/.github/workflows/checkup.yaml
@@ -8,11 +8,11 @@ jobs:
   checks:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2
 
-      - uses: r-lib/actions/setup-r@v2
+      - uses: r-lib/actions/setup-r@d3c5be51b12e724e68f33216ca3c148b66d5f0b6 # v2
 
-      - uses: r-lib/actions/setup-pandoc@v2
+      - uses: r-lib/actions/setup-pandoc@d3c5be51b12e724e68f33216ca3c148b66d5f0b6 # v2
 
       - name: Check for underscores
         run: |