diff --git a/.github/workflows/soundness.yml b/.github/workflows/soundness.yml
index 54fa5f5a..6c7d187b 100644
--- a/.github/workflows/soundness.yml
+++ b/.github/workflows/soundness.yml
@@ -97,7 +97,10 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
         with:
-          persist-credentials: false
+          # This is set to true since swift package diagnose-api-breaking-changes is
+          # cloning the repo again and without it being set to true this job won't work for
+          # private repos.
+          persist-credentials: true
           submodules: true
           fetch-tags: true
           fetch-depth: 0  # Fetching tags requires fetch-depth: 0 (https://github.com/actions/checkout/issues/1471)