During the latter part of 1964, American involvement in South Vietnam began to escalate as a result of the Gulf of Tonkin Incident. That development heralded a change in the nature of "Abnaki's" western Pacific deployments over the ensuing eight years. She departed Pearl Harbor with a dredge in tow on 4 January 1965 bound for Yokosuka, Japan. The dredge sank on the 19th; and, the following day, "Abnaki" entered Subic Bay in the Philippines. She operated locally out of Subic Bay until 5 March when she sailed for Vietnam. The tug served in Vietnamese waters as tender for a squadron of minecraft and conducted some patrols. She completed that assignment on 31 March and headed back to Subic Bay where she arrived on 4 April.