After being requisitioned by the RAN on 11 May 1941, she was sent to Darwin, Northern Territory. During the Japanese air raid on Darwin on 19 February 1942 she pulled an oil lighter clear of "Barossa", and then pulled "Barossa" away from the , only moments before "Neptuna" exploded. As the war moved away from Australia, "Wato" operated around New Guinea until 1944 before being operated out of Sydney at the end of the war. The vessel earned a single battle honour, "Darwin 1942", for her wartime service.