"Ammen" remained at Manus from 29 September until 11 October. On the latter day, she put to sea on a circuitous voyage bound ultimately for the invasion of the Philippines at Leyte. That circuit took her first to the northern coast of New Guinea where-at Humboldt Bay-she became a unit of the screen of the invasion force flagship . The flagship group weighed anchor on 15 October and laid in a course for Leyte Gulf. The destroyer escorted the command ship into Leyte Gulf in the predawn darkness of 20 October. The preparatory shore bombardment began about 0700 and lasted until just before 0945. At that point the landing craft began their approach to the beaches. Assigned to protect the force flagship, "Ammen" took no part in the festivities but watched dutifully for the intrusion of enemy aircraft and submarines. For the first five days of the Leyte undertaking, she continued to provide antiair and antisubmarine coverage to "Wasatch" and escorted her out to sea during her nightly retirements from San Pedro Bay.