USS Apollo (AS-25)...named for the Greek god of youth, manly beauty, music, and song; and who was also the god of prophecy whose oracle was located at Delphi in Greece...was laid down under a United States Maritime Commission contract, as Maritime Commission Hull 860, on 24 June 1943 by the Ingalls Shipbuilding Corporation at Pascagoula, Mississippi. The ship was christened by Mrs. James B. Hill and launched on 6 November 1943. The merchantman was acquired by, and simultaneously placed in commission in, the United States Navy on the last day of 1943 with Commander Charles D. Schutz in command.

The vessel proceeded to the Atlantic Basin Iron Works in Brooklyn, New York, and was decommissioned, there, on 14 January 1944, to undergo conversion for naval service as a submarine tender.

USS Apollo (AS-25) was recommissioned on 29 September 1944 with Captain John H. McCutchen in command.

When recommissioned as an Aegir class submarine tender (Maritime Commission Type T. C3-S-A2), USS Apollo (AS-25) was 465 feet in length at the waterline, 492 feet in length overall, and had an extreme beam of 69 feet 6 inches. The ship's Navy Light Displacement was 7,581 tons. Standard Light Displacement was 7,728 tons (at that weight, the ship had a mean draft of 23 feet). Maritime Commission deadweight tonnage was 12,515 tons. Laden Displacement was 16,500 tons with a draft of 27 feet, and her Full Load Displacement was 17,615 tons with a maximum draft of 27 feet 3 inches. Ship's compliment was 1,460 officers and enlisted men. Armament included one 5-inch, four 3-inch, four 40-mm antiaircraft, and twenty 20-mm antiaircraft guns. The ship was powered by steam geared turbines that could develop 8,500 horsepower on one propeller shaft...which was supposed to drive the ship at 18.5 knots at speed. However, best speed obtained during trials was 16.5 knots.

After loading stores, the new submarine tender got underway for shakedown in the waters near the United States Naval Submarine Base New London, Groton, Connecticut...and in Block Island Sound. Upon successful completion of sea trials, USS Apollo (AS-25) returned to the Connecticut submarine base and took on spare parts and equipment before departing Groton on 6 November 1944...bound for the Panama Canal in the Panama Canal Zone in the Republic of Panama.

USS Apollo transited the Panama Canal on 13 November; paused briefly at San Diego, California, for replenishment; and continued on to Pearl Harbor in the Territory of Hawaii.

On 10 December 1944, USS Apollo set a course for Guam in the Mariana Islands...and arrived in Apra Harbor eleven days later. The submarine tender then commenced providing services to various submarines of the United States Pacific Fleet. Her tour of duty at Guam ended on 10 July 1945...when the vessel got underway to return to Pearl Harbor. Shortly after her arrival in the Hawaiian Islands, her crew resumed submarine tending activities.

On 27 August 1945, USS Apollo commenced a transit to the east coast of the United States.

On 2 September 1945, the Second World War officially ended when representatives of the Empire of Japan signed the instruments of surrender on board battleship USS Missouri (BB-63), which was anchored in Tokyo Bay, Japan, for that occasion.

USS Apollo reached and negotiated the Panama Canal on 12 September...then continued on to New Orleans, Louisiana...where she dropped anchor in the Mississippi River on the 16th of September. The ship resumed her voyage on 30 October. She arrived at Yorktown, Virginia, on 3 November...and commenced unloading her ammunition, there, shortly after arriving at that ammunition stowage facility.

Four days later, the submarine tender steamed on to the submarine base on the Thames River in Connecticut. Upon reaching that submarine base on the 8th of November 1945, the vessel took up the task of placing submarines of the New London Group, 16th Fleet, in an inactive status.

On 16 October 1946, the status of USS Apollo was changed to "in commission, in reserve."

On 12 February 1947, USS Apollo (AS-25) was decommissioned. Subsequently, she was berthed among the inactivated submarine tenders and submarines on the Thames River in the northern portion of the United States Naval Submarine Base New London, Groton, Connecticut...as part of the Atlantic Reserve "Mothball" Fleet.

On 1 July 1963, her name was struck from the Navy List, and the vessel was transferred to the United States Maritime Administration for custody and layup in the Atlantic Reserve Fleet in the James River off Fort Eustis, Virginia.

The former submarine tender was sold to the Union Minerals and Alloys Corporation for scrapping in 1974.