Gypsy completed her shakedown training on 20 March 1946, and sailed 10 days later from Norfolk, VA for San Pedro, CA, where she arrived on 26 May. The ship then departed on 14 June to take part in the impending "Operation Crossroads", a historic series of atomic tests. Arriving off the atoll on 10 July 1946, Gypsy witnessed the "Baker" Test on 25 July and assisted in recovering beached and damaged craft and doing underwater work on test ships, as the US Navy developed a large amount of valuable scientific information on the effects of the atomic bomb on ships and how to reduce them.