On 22 September 1939 the Bulolo was requisitioned by the British Ministry of War Transport on behalf of the Royal Navy from Burns, Philp & Company Limited, (based in Sydney, New South Wales).

During this refit she had a sophisticated communications systems installed for use in army, navy and air force control purposes.

[2] She then took part in Operation Husky (the invasion of Sicily) as the flagship of Rear Admiral Thomas Troubridge in charge of 'Force A' commanding the British XIII Corps (at the Gulf of Noto) between July and August 1943, and then as flagship commanding 'Task Force Peter' embarking the British 1st Division during Operation Shingle, the landings at Anzio in January 1944.

The Bulolo then returned to Britain in April 1944 in readiness for Operation Overlord, the Allied landings being planned for Normandy in June 1944.

Following another refit, the Bulolo was sent in 1945 to be the Headquarters Ship and flagship of Rear Admiral Benjamin Martin for 'Force W' off Malaya commanding the Allies retaking of South East Asia from Japanese forces.