Neither Australia nor Antarctica have land borders with other continents, and whether Antarctica is inhabited or not (only a few hundred to a few thousand scientists) is a matter of semantics.
Australia is the only inhabited continent that does not touch any other continents. It is surrounded by the Indian and Pacific Oceans.
Antarctica is a continent that does not touch any other continents, as it is surrounded by the Southern Ocean. Australia is another continent that does not share a land border with any other continent.
Australia and Antarctica are the two continents that do not touch any other continent.
Australia and Antarctica are the two continents that do not touch any other continents directly. They are both isolated and surrounded by oceans.
Only Australia and Antarctica do not have land borders with another continent. North and South America are separated from each other by a manmade waterway, the Panama Canal, but not on the continental divide. Africa is separated from Asia by another manmade waterway, the Suez Canal, which likewise does not actually separate continents (at least not to the extent that a person could not walk from one to the other in a few steps).
Europe, Asia, and Africa touch each other at the junction known as the tripoint where the countries of Russia, Georgia, and Turkey meet. This is the only place on Earth where three continents physically connect.
Austrila
Australia and Antarctica are the two continents that do not touch any other continent.
No continent touches Antarctica: it is surrounded by the Southern Ocean.
Antarctica is surrounded by the Southern Ocean and touches no other continent.
The European continent
No continent touches Antarctica.
Antarctica is a continent that does not touch any other continents, as it is surrounded by the Southern Ocean. Australia is another continent that does not share a land border with any other continent.
Switzerland is a country in the continent of Europe. It is landlocked and all countries that surround it are also in Europe, so it does not touch any other continent.
The Atlantic and Arctic Oceans.
Europe, Asia, and Africa touch each other at the junction known as the tripoint where the countries of Russia, Georgia, and Turkey meet. This is the only place on Earth where three continents physically connect.
Antarctica and Australia.
Antarctica.