HMAS Penguin (Balmoral Naval Depot)

HMAS Penguin is a Royal Australian Navy shore establishment at Balmoral, on the lower north shore of Sydney Harbour in the suburb of Mosman, New South Wales. It forms part of Fleet Base East and is owned by the Department of Defence. The establishment is one of the RAN's principal training bases, tasked with producing trained specialists across the navy's branches, and is commanded by a commander of the RAN.

Penguin falls under Navy Systems Command and occupies a site of some 14.2 hectares. It hosts the ADF Diving School, the RAN Hydrographic School and the RAN Medical School, together with the RAN Leadership and Management Development Centre. Medical and underwater-medicine functions concentrated at the site include the Submarine and Underwater Medicine Unit, the RAN Recompression Chamber Facility, the Maritime Operational Health Unit, the ADF Centre for Mental Health and the Penguin Health Centre. Since 2006 Headquarters and 1st Commando Company of the 1st Commando Regiment have been accommodated at Penguin as lodger units. Naval hospital care, previously provided on site by the Balmoral Naval Hospital until its closure in 2006, is contracted to St Vincent's Hospital at Darlinghurst; the hospital had furnished trained personnel for the Primary Casualty Receiving Facilities aboard the Kanimbla-class vessels.

The site was established as the Balmoral Naval Depot, serving the main naval base at Garden Island, and was known as Penguin II from 1941. Commissioned in July 1942 with accommodation for 700 personnel, administrative facilities and the Balmoral Naval Hospital, it was renamed HMAS Penguin in January 1943 when the Garden Island establishment became HMAS Kuttabul, and also based the motor launches patrolling Sydney Harbour. From 1945 the depot was converted to training use, housing the RAN Seamanship School from 1945 to 1974, the National Service Recruit School from 1951 to 1954, and later the RAN Staff College and the Security and Naval Police Coxswains School; operational units formerly based there included Clearance Diving Teams One and Two and the Royal Navy's 4th Submarine Squadron, disbanded in 1969.