diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index d70e8b0..9ccac3c 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -34,14 +34,14 @@ jobs:
       fail-fast: false
       matrix:
         config:
-          # - {os: macOS-latest,   r: 'devel'}
-          # - {os: macOS-latest,   r: 'release'}
+          - {os: macOS-latest, r: 'devel'}
+          - {os: macOS-latest, r: 'release'}
           - {os: windows-latest, r: 'devel', rtools: '44', http-user-agent: 'release'}
           - {os: windows-latest, r: 'release', rtools: '43'}
           - {os: windows-latest, r: 'oldrel', rtools: '42'}
-          # - {os: ubuntu-latest,   r: 'devel', http-user-agent: 'release'}
-          # - {os: ubuntu-latest,   r: 'release'}
-          # - {os: ubuntu-latest,   r: 'oldrel'}
+          - {os: ubuntu-latest, r: 'devel', http-user-agent: 'release'}
+          - {os: ubuntu-latest, r: 'release'}
+          - {os: ubuntu-latest, r: 'oldrel'}
 
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}