Sydney made history for the RAN on November 9, 1914, off the Cocos Islands in the Indian Ocean. Detached from convoy escort duty to investigate the reported "strange warship approaching" from the Cocos Islands WT Station, Sydney came into action with the German light cruiser SMS Emden. The action lasted over an hour and resulted in the Emden being wrecked and driven onto North Keeling Island reef.
During the remainder of World War I Sydney served in UK waters. In 1918 she operated a Sopwith Pup, launched from a platform fitted over a gun mounting. After the war Sydney continued to serve on the Australian station, including a period spent as flagship. She was paid off in 1928 and scrapped in Sydney in 1929.
The second Sydney a modified Leander-class light cruiser was built at Wallsend-on-Tyne, England, between 1933 and 1935. Originally she was to have been HMS Phaeton but was purchased and renamed by the Australian Government before she was launched. Her brief career during World War II earned four of the seven battle honours which the present ship bears.
Her crowning glory was achieved on July 19, 1940, off Cape Spada in the Greek Islands. With a British destroyer squadron in company, she met the two high-speed Italian light cruisers Giovanni delle Bande Nere and Bartolomeo Colleoni. In the running battle which followed, Colleoni was wrecked and later sunk by destroyers' torpedoes. Only the very high speed of Bande Nere saved her from a similar fate. While serving in the Mediterranean, Sydney was also credited with the sinking of the Italian destroyer Espero and shared honours in the sinking of the destroyer Zeffiro during the Battle of Calabria.
Sydney met her end tragically on November 19, 1941, 150 miles west of Shark Bay, Western Australia. There she met and was surprised by the disguised German armed merchant raider Kormoran. Though Sydney managed to sink Kormoran, she herself was lost with her whole complement of 645 men.
The third Sydney was laid down at Devonport, England, as the Majestic-class light aircraft carrier HMS Terrible in 1943. She was commissioned in December, 1948. She was equipped with Hawker Sea Fury fighter and Fairey Firefly attack aircraft.
In 1951 and 1952 Sydney operated with the United Nations forces in Korean waters. She participated in many actions and created a light fleet carrier record when she achieved 89 aircraft sorties in one day.
The ship continued in service as a carrier until 1955 when her newer sister ship, HMAS Melbourne, took over the RAN's aircraft carrier role. Sydney then served as a training ship until she was decommissioned in 1958. However, in 1962 she was reactivated and converted to a fast troop transport until her eventual retirement in 1973. During the period Sydney was the training ship for many new members of the RAN and from 1965 she was heavily committed to the support of the Australian Task Force in Vietnam. All together she made 24 troop transport visits to Vietnam, which earned her the nickname "Vung Tau Ferry".
The fourth Sydney (FFG-03) was an Oliver Hazard Perry-class frigate purchased from the United States. Her keel was laid down August 21, 1980. She was launched September 26, 1980, and commissioned into the RAN on January 29, 1983.