From June through August 1959, the
Charleston Navy Yard in
South Carolina removed all of
Requins radar equipment and improved her streamlining. Upon her conversion to Fleet Snorkel configuration, she was given hull classification symbol SS-481' on 15 August 1959, and rejoined SubRon 6 in Norfolk for operations as a normal attack submarine, a role she retained until her decommissioning.
Requin conducted local operations off the East Coast and in the
Caribbean Sea. In the summer of 1961,
Requin served as a target for Task Group Alpha led by USS
Saratoga CVA 60.
Requin conducted a periscope approach on
Saratoga and launched a simulated torpedo attack. Then a helicopter dropped an exercise torpedo on
Requin, which hit forward and made several re-attacks bouncing down the port side of the submarine. On 20 September 1963,
Requin completed her 5000th dive. From 7 January 1964 into May, she operated with the Sixth Fleet, then resumed her Second Fleet duties into 1968, interrupted only twice for extended deployments. Operation UNITAS VII in the fall of 1966 called for
Requin to cruise around the
South American continent for exercises with various South American navies. Her last Sixth Fleet deployment sent her back to the Mediterranean for duty from 4 April to 27 July 1967.
Requins last Mediterranean deployment began on 4 April 1967. On 8 June, just as she completed a series of exercises with the
U.S. Sixth Fleet, she received word that the U.S. signals intelligence ship was under attack.
Requins crew prepared to go to the defense of
Liberty, but received orders from the Sixth Fleet commander to surface and proceed to
Crete. On 28 May 1968, during her last deployment before decommissioning,
Requin departed
Norfolk, Virginia, as part of the search effort for the missing nuclear attack submarine . On 29 June 1968,
Requin was reclassified as an auxiliary submarine,
AGSS-481, and in October 1968 she began inactivation at
Naval Station Norfolk. ==Decommissioning and disposal==