Built by the Portsmouth Navy Yard of New Hampshire, the USS Sirago (SS-485), a Tench -class submarine named for a tropical freshwater fish, was launched on 13 May 1945 and commissioned on 13 August 1945. Measuring 311 feet 8 inches long, and displacing more than 1,800 tons surfaced and 2,400 tons submerged, the Sirago was armed with ten 21-inch torpedo tubes. The Sirago conducted her shakedown cruise off the East Coast and in the Caribbean under Commander F. J. Harlfinger II, the boat's first commanding officer.
Upon joining Submarine Squadron 8 (SubRon 8) she transferred to New London, Connecticut, and in January 1946 took part in the destruction of two German submarines near Provincetown, Massachusetts. The Sirago participated in several training operations until December 1948, when she began a GUPPY II conversion at the Philadelphia Naval Shipyard. Upon completion of her conversion in July 1949, she was a modern high-speed attack submarine and joined SubRon 6 in Norfolk, Virginia.
As an integral part of SubRon 6, the Sirago trained for antisubmarine and antisurface operations, intelligence gathering, and research and development projects. The Sirago operated primarily in the Western Atlantic and took part in numerous U.S. and international naval exercises, including several with the Canadian Navy and the North Atlantic Treaty Organization. The Sirago also deployed to the Mediterranean during the 1950s and operated as part of the U.S. Navy's Sixth Fleet during the fall of 1951 and the fall of 1954.
October 1962 marked an important milestone in the life of the Sirago , as she underwent an extensive overhaul and was given a new fiberglass superstructure and sail. Following this overhaul, she rejoined her antisubmarine warfare group and later that year deployed to the Middle East for CENTO exercise MIDLINK VI.
For nearly ten years, the Sirago took part in numerous training operations. She was reassigned to SubRon 12 at Key West, Florida, in July 1971. Less than six months later, however, she rejoined SubRon 6 in Norfolk, Virginia. She remained an essential contingent of SubRon 6 until her decommissioning on 1 June 1972. She was sold for scrap on 2 May 1973.