Australia is the largest sovereign state bordering the Indian Ocean.
Australia covers about 7.69 million square kilometres, making it the world’s sixth-largest country. Its western and southern shores face the Indian Ocean, while its northern and eastern waters connect with seas and ocean regions associated with the Pacific.
Australia is both a country and a continent. Its mainland is surrounded by the Indian, Pacific and Southern ocean regions, and the country also includes Tasmania and many smaller islands. Its Indian Ocean coastline includes Western Australia and South Australia.
India is the largest country whose mainland lies directly on the northern Indian Ocean, but it is smaller than Australia. Indonesia is also a major Indian Ocean state, especially through Sumatra and Java, yet its total area is lower. Definitions of ocean boundaries can vary locally, but Australia is the clear area leader among sovereign states commonly classed as Indian Ocean countries.