While under construction Yustaga was redesignated a submarine rescue ship on 11 October 1945, assigned the hull designation ASR-20 on 13 November 1945, and renamed Skylark on 5 December 1945.

In June, she returned to New London and carried out her training schedule until October when she again headed back to Norfolk to substitute for Kittiwake, while the latter participated in "Operation Springboard."

In February and March 1954, Skylark engaged in her own share of "Operation Springboard" exercises, providing services to Atlantic Fleet submarines during the annual training evolution.

The one notable exception to that pattern occurred in January and February 1955 when she assisted Nautilus (SSN-571), the Navy's first nuclear-powered submarine, in completing her builders' trials.

At the beginning of 1962, Skylark began a new phase of her career when regular deployments to the 6th Fleet in the Mediterranean became a normal aspect of her activities and continued to be for the remainder of her naval service.

During the latter portion of that cruise, Skylark served for several weeks at the ballistic missile submarine base located in Holy Loch, Scotland, before returning home to New London on 29 October.

During the remaining eight years of her Navy career, the ship alternated duty along the Atlantic coast of the United States with deployments to the Mediterranean and to the submarine base at Holy Loch.

Her only other major departure from her routine came in June 1972 when she participated in NATO Exercise "Pink Lace" before beginning a scheduled deployment to Holy Loch and the Mediterranean in July.

During the early part of the deployment, Skylark performed operational exercises with both U.S. and U.K. boats out of Faslane, Scotland, and researched alternate egress possibilities from Holy Loch into the North Sea.