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.

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.

Early in January 1946, she arrived at Newport, Rhode Island, her assigned homeport, and began local operations in submarine training and other exercises.

Continuing her coastwise and Caribbean operations, she acted as plane guard during anti-submarine exercises, was schoolship for the Fleet Sonar School at Key West, Florida, and during the summer of 1954 called at ports in Ireland and England on a midshipman training cruise.

Assigned permanently to the Fleet Sonar School at Key West on 22 August 1957, Coolbaugh thereafter operated primarily in Florida waters, often cruising with members of the Naval Reserve on board for training.