The first USS Estero (CVE-42) (previously AVG-42 then later ACV-42) was an escort aircraft carrier launched 22 March 1943 by the Seattle-Tacoma Shipbuilding Corporation, Seattle, Washington, and sponsored by Mrs. C. N. Ingraham. She was reclassified CVE-42 on 15 July 1943. Completed in October 1943, she was transferred to the Royal Navy on 3 November 1943 and commissioned the same day as HMS Premier.