Between 19 and 27 November 1944, "Coolbaugh" screened escort carriers as they provided air cover for convoys supplying forces in Leyte Gulf, and then sailed to New Guinea to prepare for the Lingayen assault. Through January and February 1945, she screened transports carrying reinforcements to Lingayen Gulf, serving on patrol within the gulf during each such voyage. Between 28 February and 4 March, she sailed from Ulithi to Iwo Jima to carry away men who had made the original landings, upon their relief by other forces. She returned to Iwo Jima to patrol off the island until 27 March, when she cleared for Pearl Harbor.