Which Countries Border Australia?

As Australia is an island, it has no land borders with other nations.
As Australia is an island, it has no land borders with other nations.

Australia is a unique country as it is the world's only country that is also a continent. Wildlife in Australia is also unique as they evolved independently of species anywhere else in the world. Humans have lived in Australia for more than 40 millennia with the first inhabitants of the country descending from some of the first groups to migrate from Africa. Australia covers nearly 3 million square miles most of which is either arid or semi-arid. No country borders Australia in the traditional sense due to its unique geographical position, but it does share maritime borders with some nations.

Countries Sharing Maritime Borders with Australia


Australia and Indonesia share a maritime border described by four signed treaties one of which is yet to be ratified. The two countries were previously engaged in a heated dispute over control of the area. The first two treaties between the nations caused some discontent among the Indonesians as the method used to decide the border's location had the potential to deny Indonesia oil reserves. The final treaty, signed in 1997, included elements of both countries arguments to determine the location of the border.


Timor-Leste is a 5,400 square mile nation that gained independence in 2002 and occupies the eastern section of the Timor Island. The western half is under Indonesian control. In 2018, Australia and Timor-Leste signed a treaty that established a permanent maritime border between the two. The primary dispute between the countries was how they were going to share oil and gas resources located in the border region.

Papua New Guinea

Australia once ruled Papua New Guinea, and in 1975 Papua New Guinea became a sovereign state. In 1978, Australia and Papua New Guinea signed a treaty that defined the maritime border between the two countries. The agreement has been feted on how it addressed boundary challenges that affected the lives of the native people. Australia has a couple of islands that are within Papua New Guinea's side of the border.

Solomon Islands

The maritime boundary between Australia and the 11,000 square mile nation of Solomon Islands was signed in 1988 and came into effect the following year. The two countries, both members of the commonwealth, have strong bilateral relations with Australia contributing significant quantities of foreign aid to the nation.

New Zealand

In 2004, in the city of Adelaide, Australia and New Zealand signed a treaty to establish the boundary between the two countries which became effective in 2006. The agreement was the official recognition of borders the two countries had adhered to since the 1980's.

New Caledonia

James Cook, the first European to see the area, named it New Caledonia as it reminded him of Scotland. The treaty detailing the border between Australia and French controlled New Caledonia was signed in 1982 and came into effect a year later.


Vanuatu is a 4,700 square mile nation located to the northeast of Australia. The relationship between the two countries is exceptionally cordial with Australia investing heavily in Vanuatu and donating vast quantities of foreign aid.

Maritime Borders

Nations place great value on their maritime borders due to the vast quantity of resources located in those regions. Maritime borders have caused conflicts between many countries over the years. However, negotiation usually solves those disagreements before they can escalate further.


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