Through June 1945 "O'Bannon" operated primarily in the Philippines, serving in the escort or assault force for the long roll call of invasions: Ormoc Bay, Mindoro, Lingayen Gulf, Bataan, Corregidor, Palawan, Zamboanga, Cebu, and Caraboa. Air attacks were frequent in the early period, and "O'Bannon" splashed several raiders. During the Lingayen offensive on 31 January 1945, "O'Bannon", with three other destroyers, attacked and sank an enemy submarine; Japanese records studied after the war indicate it was most likely . At the end of April and early in May, "O'Bannon" interrupted her Philippine operations to give fire support at Tarakan, Borneo, and cover minesweeping operations there.