On 13 July 1943, Leander was with Rear Admiral Walden Lee Ainsworth's Task Group 36.1 of three light cruisers:  Leander and the US ships Honolulu and St. Louis. The task group also included ten destroyers. At 01:00 the Allied ships established radar contact with the Japanese cruiser Jintsu, which was accompanied by five destroyers near Kolombangara in the Solomon Islands. In the ensuing Battle of Kolombangara, Jintsu was sunk and all three Allied cruisers were hit by torpedoes and disabled. Leander was hit by a single torpedo just abaft 'A' boiler room. 26 crew from the boiler room and the No.1 4-inch gun mount immediately above were killed or posted missing.^[2] The ship was so badly damaged that she took no further part in the war. She was first repaired in Auckland, then proceeded to a full refit in Boston.

The remains of several of the crew remained trapped within the damaged vessel and were removed at Auckland.