Estero, which originally served with the U.S. Army as USA FS-275, was acquired by the U.S. Navy in March 1947 and commissioned on 5 July.

She was employed in logistics support of the administration of the United Nations Trust Territories, calling throughout the Marshalls, Carolines, and Marianas.

At the outbreak of the Korean War she was fitted out for emergency ammunition carrying service, participating thereafter in the Inchon invasion in September 1950.

From 25 August to 2 September 1954 she made five trips in support of "Operation Passage to Freedom", the evacuation of refugees from North Vietnam.

Subsequently she performed her logistics services for the fleet in the western Pacific, with only brief interludes as in May through July 1957 when she transported an Air Force team which was surveying the habitability of prospective stations in the Sulu Sea.