diff --git a/x-pack/legacy/plugins/ml/public/application/services/ml_api_service/index.ts b/x-pack/legacy/plugins/ml/public/application/services/ml_api_service/index.ts
index a2310c591671df..2f6ce24b93e47f 100644
--- a/x-pack/legacy/plugins/ml/public/application/services/ml_api_service/index.ts
+++ b/x-pack/legacy/plugins/ml/public/application/services/ml_api_service/index.ts
@@ -474,7 +474,7 @@ export const ml = {
   /**
    * Gets a list of calendars
    * @param obj
-   * @returns {Promise<unknown>}
+   * @returns {Promise<Calendar[]>}
    */
   calendars(obj?: { calendarId?: CalendarId; calendarIds?: CalendarId[] }) {
     const { calendarId, calendarIds } = obj || {};