diff --git a/changelogs/unreleased/ci_default_git_depth_only.yml b/changelogs/unreleased/ci_default_git_depth_only.yml
new file mode 100644
index 0000000000000000000000000000000000000000..928e2fe3ec49355fc561fb9d8e15405906ad836a
--- /dev/null
+++ b/changelogs/unreleased/ci_default_git_depth_only.yml
@@ -0,0 +1,5 @@
+---
+title: 'API: Allow changing only ci_default_git_depth'
+merge_request: 30888
+author: Mathieu Parent
+type: fixed
diff --git a/lib/api/helpers/projects_helpers.rb b/lib/api/helpers/projects_helpers.rb
index 833e3b9ebafee7f76aa33896d6b0676191dbb889..51b7cf05c8f88991edb542a75caff2a961780cd2 100644
--- a/lib/api/helpers/projects_helpers.rb
+++ b/lib/api/helpers/projects_helpers.rb
@@ -71,6 +71,7 @@ module API
           :build_timeout,
           :builds_access_level,
           :ci_config_path,
+          :ci_default_git_depth,
           :container_registry_enabled,
           :default_branch,
           :description,