Deploying again to the Mediterranean as a radar picket submarine from 5 March to 4 June 1956, she operated with NATO and U.S. Navy units. The remaining months of "Ray'"s operating schedule in 1956 and 1957 were involved in type training and fleet exercises in the Atlantic and Caribbean, including representing Submarine Force, U.S. Atlantic Fleet, at the International Naval Review at Hampton Roads in June 1957 and participating in the NATO Exercise "Strikeback" held off Scotland, France, and Portugal in September and October 1957. The early part of 1958 was spent in fleet exercises off the east coast and the Caribbean.