Patrol Squadron 13 (VP-13) was established on 1 July 1940, formed at Naval Air Station San Diego, California, from personnel from VP-14. Equipped with PB2Y-1 Coronado flying boats, the squadron began flying long surveillance patrols and flights to bases in the Pacific to deliver personnel and supplies. A flag transport detachment was established at NAS Kaneohe Bay, Hawaii.
In April 1942, VP-13 received PB2Y-2 versions and assumed transition training crews destined for other PB2Y squadrons. In June, the squadron received its first PB2Y-3, and in November, the flag detachment was recalled from Kaneohe. However, in January 1943, VP-13 moved as a unit (with 12 PB2Ys) to Kaneohe and began regular patrols around Hawaii and special transport runs.
In December 1943, the PB2Y-1/2 versions were replaced by new PB2Y-3s, four of which were converted to PB2Y-3H ambulance aircraft and sent to the Gilbert Islands.