Departing Hollandia, New Guinea, on 12 October 1944, "Gallup" was part of the screen for the task force which mounted the invasion of Leyte in the Philippine Islands. On 17 October 1944, she shelled the beach area of Dinagat, and the next day she swept the channel into Leyte Gulf as U.S. forces poised for the invasion. She then began anti-submarine and anti-mine patrol near Black Beach, screening vessels engaged in landing operations. Stationed most of the time off Desolation Point, she collected tide and hydrographic information, served as dispatch boat and as escort through the cleared channel in Leyte Gulf, guided incoming ships and convoys through the channel, and served as harbor entrance control vessel during landing operations. She performed these duties, most of the time in gusty, stormy weather, with her sister ship and the large infantry landing craft and , before being sent on an escort mission to Humboldt Bay, New Guinea, on 28 November 1944, touching San Pedro Bay in the Philippines, Kossol Roads in the Palau Islands, and Manus in the Admiralty Islands "en route".