|Owner:||Sydney Ferries Limited|
|Operator:||Sydney Ferries (1922-1940)|
|Port of registry:||1922-1940: Sydney, Australia|
|Builder:||Walsh Island Dockyard and Engineering Works, Newcastle|
|Length:||182.6 ft (55.7 m)|
|Beam:||36.1 ft (11.0 m)|
HMAS Koompartoo was a Royal Australian Navy (RAN) auxiliary boom defence vessel, and former Sydney harbour ferry.
Built in 1922 by the Walsh Island Dockyard and Engineering Works in Newcastle, New South Wales. Koompartoo was constructed with 18 watertight compartments, regarded as being unsinkable and therefore was not required to carry lifebelts.
After service with Sydney Ferries, she was purchased by the British Ministry of War Transport for service in the Middle East and began conversion work at Mort's Dock, Sydney. With the outbreak of war in the Pacific, she was transferred to the RAN in October 1942 and was commissioned on 23 December 1942.