From June to August 1944, "Callaghan" provided screen for escort carriers softening up, and later supporting the invasions of Saipan, Tinian, and Guam. At Saipan, "Callaghan"s guns joined in driving off a heavy Japanese air attack on 17 June, helping shoot down three enemy aircraft. was struck by a bomb in this attack, and "Callaghan" escorted the crippled escort carrier safely back to Eniwetok. Late in August "Callaghan" began operations as escort for air strikes on the Palaus, Mindanao, Luzon, and the Central Philippines in support of the invasion of the Palaus, a stepping stone to the Philippines.