American-British-Dutch-Australian Command
Following the Japanese attack on Pearl Harbor, "Barker" operated with the American-British-Dutch-Australian Command (ABDACOM) in Southeast Asian and Australian waters until May 1942, then escorted convoys between San Francisco, California, and Pearl Harbor, Hawaii until May 1943, when the destroyer transferred to the Atlantic Fleet to join Task Group 21.12, a hunter-killer group centered on the escort carrier "Core".