Australia’s external territories including Heard Island and the McDonald Islands, the Australian Antarctic Territory, Ashmore and Cartier Islands and the Coral Sea Islands, as well as the mainland Territory of Jervis Bay, have no insignia or emblems. Their symbols are the Commonwealth Coat of Arms and the Australian National Flag.

The Christmas Island flag was formally declared on 26 January 2002 by the then Administrator of the territory, Bill Taylor. The flag of Christmas Island was chosen from a flag competition held in 1986 and announced on 14 April 1986. The blue and green triangles represent the sea surrounding the island and the vegetation of the island. The Southern Cross in the blue triangle is the representation appearing in the Australian National Flag. The image in the green triangle is the golden bosun bird, which is unique to the island. The gold disk in the centre of the flag represents the island’s phosphate mining history and was originally included to provide a background for the green map of Christmas Island.

The flag of the Cocos (Keeling) Islands was created in 2003 and formally declared on 6 April 2004 by the then Administrator of the territory, Evan Williams. The flag of the Cocos (Keeling) Islands is green, with a coconut palm tree circled with a yellow colour on the top left side of the flag. There is also a yellow crescent in the centre of the flag and 5 seven-pointed stars on the right side of the flag.