During the Battle of Coral Sea in the South Pacific, his 5th Carrier Division successfully sank the American carrier , but "Shōkaku" was heavily damaged by bombs and a large number of planes and pilots from "Zuikaku" were lost. These damages put both aircraft carriers out of the war for many months, and they both missed the Battle of Midway. Meanwhile, Hara was reassigned to command the 8th Cruiser Division, containing the large, fast heavy cruisers and , and their escorting destroyers, during the long, bitter struggle with the Americans for the Solomon Islands. Hara and his warships were present for two large battles in the South Pacific: the Battle of the Eastern Solomons and the Battle of the Santa Cruz Islands.