diff --git a/.github/workflows/foundry.yml b/.github/workflows/foundry.yml
index 2d60f84c..76e9eb80 100644
--- a/.github/workflows/foundry.yml
+++ b/.github/workflows/foundry.yml
@@ -23,7 +23,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+        with:
+          submodules: recursive
       - uses: foundry-rs/foundry-toolchain@908c540300062bd5a7e473851cdb4282204cee09 # v1.9.1
+      - name: Check foundry.lock matches submodule pins
+        run: forge build --locked
       - run: forge test -vvv
         env:
           FOUNDRY_FUZZ_RUNS: 10000