At the start of World War II, Canberra was initially used for patrols and convoy escort around Australia. In July 1940, she was reassigned as a convoy escort between Western Australia, Sri Lanka, and South Africa. During this deployment, which ended in mid-1941, Canberra was involved in the hunt for several German auxiliary cruisers. The cruiser resumed operations in Australian waters, but when Japan entered the war, she was quickly reassigned to convoy duties around New Guinea, interspersed with operations in Malaysian and Javanese waters. Canberra later joined Task Force 44, and was involved in the Guadalcanal Campaign and the Tulagi landings.