What ocean is south of Australia?

The Southern Ocean lies to the south of Australia, separating the continent from Antarctica. It is the world's fourth-largest ocean and the only one that circles the planet without being interrupted by land, flowing eastward around Antarctica through the Antarctic Circumpolar Current.

The Southern Ocean's existence as a distinct ocean was formally recognised by the International Hydrographic Organization in 2000 and again, more definitively, by the United States National Geographic Society in 2021, which began labelling it on its maps. Its boundary with the Atlantic, Pacific, and Indian oceans is conventionally drawn at 60 degrees south latitude. Australia and several other countries also recognise the ocean as extending further north to the southern coast of the continent.

The Australian coastline on the Southern Ocean runs along the southern shore of Western Australia, all of South Australia, southern Victoria, and the south and west of Tasmania. The Great Australian Bight, the broad open bay south of the Nullarbor Plain, is the most prominent feature. Major ports include Esperance and Albany in Western Australia, Port Lincoln and Whyalla in South Australia, and Portland in Victoria.

The Southern Ocean influences Australian climate through the polar fronts and westerly winds known as the Roaring Forties (40 to 50 degrees south) and Furious Fifties (50 to 60 degrees south). These winds drive the cold, wet weather systems that bring winter rainfall to southern Australia and Tasmania. Australian Antarctic stations at Casey, Davis, and Mawson are supplied by icebreakers crossing the Southern Ocean from Hobart each summer, and the Australian Antarctic Territory covers about 42 per cent of the continent.