After commissioning the light cruiser got underway on 5 January 1945 for shakedown training in the Chesapeake Bay and the Caribbean. Upon the completion of those exercises, "Atlanta" arrived at Norfolk, Virginia, on 14 February and then moved up the coast to Philadelphia. After a period in the navy yard there, she sailed on 27 March for the Pacific. She stopped at Guantanamo Bay, Cuba, and transited the Panama Canal before reaching Pearl Harbor on 18 April. From 19 April to 1 May, the ship conducted training exercises in Hawaiian waters. She then sailed to Ulithi and reported to Task Force 58 on 12 May.