diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index e664e5f..f3502f2 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -15,6 +15,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+    - name: Checkout submodules
+      uses: textbook/git-checkout-submodule-action@2.1.1
     - name: Set up JDK 16
       uses: actions/setup-java@v2
       with: