In January 1945 4ACS and 5ACS moved to Biak island where they worked on improving facilities used by the US Army and United States Army Air Forces (USAAF). In mid-May 1945 4ACS and 5ACS traveled together to Morotai. They remained on this island until June when they departed as part of the Australian-led Battle of North Borneo. The two squadrons landed at Labuan on 11 June and worked on repairing and maintaining the island's airfield until the end of the war on 15 August.