The USS Nereus (AS-19) was a submarine tender of the United States Navy, launched on 24 March 1944. Designed to support submarines, it provided maintenance, supplies, and repair services. The ship was named after Nereus, a figure from Greek mythology known as the "Old Man of the Sea." Commissioned on 1 December 1944, the USS Nereus served primarily in the Pacific Theater during World War II. After the war, it continued to operate, supporting various submarine operations until it was decommissioned in 1991. The ship played a vital role in enhancing the operational capabilities of the U.S. Navy's submarine fleet.