Copahee is a sound on the South Carolina coast. Todd-Pacific at Tacoma launched her on 21 October 1941 under a Maritime Commission contract. Mrs. W. M. Wells sponsored her. The Navy acquired her on 8 February 1942, and Commander J. G. Farrell commissioned her on 15 June 1942. She was carried first as AVG-12, then ACV-12 from 20 August 1942, and CVE-12 from 15 July 1943.
She sailed from Alameda on 5 September 1942 and reached Noumea on 28 September with planes, stores, and passengers. From 7 to 11 October she cruised toward Guadalcanal and launched twenty Marine fighters for Henderson Field. She was back at San Diego on 29 October for overhaul.
After training at Pearl Harbor she left San Diego on 25 February 1943 and, through 7 June, carried aircraft, aviation stores, and men to the New Hebrides, Fiji, New Caledonia, and Hawaii. Between 2 September 1943 and 19 January 1944 she made two voyages to Townsville and Brisbane and one to Pearl Harbor. From 10 April she ferried aircraft from Pearl Harbor to Majuro. On 3 June she began supplying replacement pilots and aircraft to the carriers of the Fifth Fleet for the Marianas. She returned to San Diego on 28 July with captured Japanese planes and equipment.
After overhaul she went back to transport duty and made six voyages from Alameda to Manus, Majuro, Guam, Saipan, and Pearl Harbor. From 6 September to 21 December 1945 she brought servicemen home from Saipan, Guam, Eniwetok, and the Philippines. She reached Alameda on 21 December 1945 and was decommissioned, in reserve, at Tacoma on 5 July 1946. She received one battle star. On 12 June 1955 she was redesignated CVHE-12. Her name was struck on 1 March 1959, and she was sold on 1 February 1961.