On 29 January 1943, with her sister ship Kiwi, Moa helped ram and wreck the Japanese submarine I-1. At the time Moa was under the command of Lieutenant Commander Peter Phipps, later Vice Admiral Sir Peter Phipps. On 7 April 1943, Japanese aircraft sank Moa at Tulagi Harbour in the Solomon Islands. The ship sustained a direct hit from a 500-pound bomb and sank within four minutes. Five ratings were killed and seven were seriously wounded. Moa was the first of two boats with this name to serve in the Royal New Zealand Navy and was named after a native bird from New Zealand.