Oceania is a geographical region comprising Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern and Western Hemispheres, at the centre of the water hemisphere, Oceania is estimated to have a land area of about 9,000,000 square kilometres (3,500,000 sq mi) and a population of around 44.4 million as of 2022. When compared to the continents, Oceania is the smallest in land area and the second-least populated after Antarctica.

Melanesia is a subregion of Oceania in the southwestern Pacific Ocean. It extends from New Guinea in the west to the Fiji Islands in the east, and includes the Arafura Sea.