On 5 October, she sailed for Pearl Harbor, arriving on 11 October. "Laffey" operated in Hawaiian waters until 21 May 1946, when she participated in Operation Crossroads, the atomic bomb tests at Bikini Atoll, actively engaged in collecting scientific data. Radioactive decontamination of "Laffey" required the "sandblasting and painting of all underwater surfaces, and acid washing and partial replacement of salt-water piping and evaporators." Upon completion of decontamination, she sailed for the west coast via Pearl Harbor arriving San Diego on 22 August for operations along the west coast.