Xanthus (AR-19) was laid down under Maritime Commission contract (MCE hull 2664) as Hecla on 6 June 1944 at Baltimore, Md., by the Bethlehem-Fairfield Shipyard, Inc.; launched on 31 July 1944; sponsored by Mrs. J.W.A. Waller; delivered to the Navy on a loan basis on 16 August 1944; renamed Xanthus and designated AR-19 on 6 December 1944; and commissioned on 9 May 1945, Comdr. Stanley G. Nichols in command.
Following training operations and a transit of the Panama Canal, Xanthus arrived at Pearl Harbor on 20 July to serve there as a repair ship. On 11 August, she sailed for Adak, Alaska, to join forces massing there for the projected assaults on the Kurils and northern Japan. The Japanese capitulation, however, obviated such operations. Instead of an invasion, there was now an occupation.
As part of Task Group (TG) 40.2, Xanthus proceeded to Japan and arrived at Ominato on 9 September-the same date that Japanese forces there surrendered to Vice Admiral Frank Jack Fletcher. The ship remained at Ominato through 21 November, serving as flagship for the commander of TG 56.2, the repair and logistics group. Subsequently reporting for duty with Service Squadron 104, the ship operated out of Okinawa through late January 1946.
On 10 February 1946, Xanthus sailed for Tsingtao, China, and helped to stabilize troubled conditions there in the wake of the Japanese withdrawal. As Communist and Nationalist Chinese jockeyed for position in the volatile situation in their country, Xanthus supported American naval activities in that port until sailing for home on 8 April 1946.
Subsequently arriving at Norfolk, Va., in the spring of that year, the repair ship was laid up at the Maritime Commission facility in the James River, Va., in an "on hand" status, through 1961. On 1 September 1962, the ship was struck from the Navy list.