diff --git a/tools/ci/ci_wpt.sh b/tools/ci/ci_wpt.sh
index 2a1eac84bfd787d..94570420d0d1e51 100644
--- a/tools/ci/ci_wpt.sh
+++ b/tools/ci/ci_wpt.sh
@@ -8,6 +8,7 @@ cd $WPT_ROOT
 source tools/ci/lib.sh
 
 main() {
+    git checkout --unshallow https://github.com/w3c/web-platform-tests.git +refs/heads/*:refs/remotes/origin/*
     hosts_fixup
     install_chrome unstable
     pip install -U tox codecov