Which country is both an island and a continent?

Australia is considered both an island and a continent due to its unique geographical characteristics. It is the smallest continent in the world and is surrounded by water, which qualifies it as an island as well. The definition of a continent can vary, but in the case of Australia, it meets the criteria for being both because it is a large landmass that is distinct and surrounded by oceans.

In contrast, New Zealand, Japan, and Madagascar, while also islands, do not meet the criteria to be classified as continents. New Zealand is part of the continent of Zealandia, which is a submerged continental fragment that does not fit the traditional definition of a continent. Japan is an archipelago composed of several islands and does not constitute a continent. Madagascar, while a significant island, is not classified as a continent in its own right, as it is much smaller than Australia and does not meet the criteria set for continents. Thus, Australia stands out as the only place fitting the criteria of being both an island and a continent.