After the Pacific and Atlantic oceans, the Indian Ocean is the world's third largest ocean. It encompasses 73,556,000 square kilometres, or 20 percent of the earth's water surface. It is bordered on the north by Asia (which includes the Indian subcontinent), the west by Africa, the east by Indonesia, the Sunda Islands, and Australia, and the south by the Southern Ocean. The Indian Ocean is separated from the Atlantic Ocean by a line going south from Cape Agulhas at 200 east longitude, and from the Pacific Ocean by a line at 1470 east longitude. At the southernmost points of Africa and Australia, the ocean is approximately 10,000 kilometres wide.

The International Hydrographic Organization established a fifth world ocean by separating the southern Indian Ocean from the rest of the ocean. The new ocean stretches north from Antarctica's coast to 60⁰ degrees south latitude, which is the Antarctic Treaty Limit. As a result, the Indian Ocean's southernmost limit has been set at 60⁰ degrees south, separating it from the Antarctic Ocean. The Indian Ocean is still the world's third largest of the five oceans. South of 65⁰  south latitude, pack ice and icebergs can be found all year. Icebergs have an average northern limit of 45⁰ degrees south latitude.

Its location in the south of India gives it significant geopolitical, sociocultural, and economic significance. The Indian Ocean, named after India, is the only ocean in the world to be named after a country. India's strategic importance in the Indian Ocean cannot be overstated. The Indian Ocean's landlocked character has given India a dominant position. The fact that it is only accessible from the west and east through the narrow straits adds to the strategic importance of this ocean. In the west, the Red Sea is the narrow exit, while in the east, the Strait of Malacca and the Timor and Arafura seas are the narrow outflows.

The Indian Ocean is linked to the Mediterranean Sea and Europe via the Suez Canal. India was connected to Europe and America via the Cape of Good Hope prior to the Suez Canal's inauguration in 189. (South America). Controlling these outlets has the potential to choke the Indian Ocean at any point. Bab-al-Mandeb, the Strait of Hormuz, the Strait of Malacca, the southern approach to the Suez Canal, and the Lombok Strait are the primary choke points.

The ocean is surrounded by 47 littoral countries, seven island countries (Madagascar, the world's fourth largest island, the Comoros, Seychelles, Maldives, Mauritius, Singapore, and Sri Lanka), and thirteen landlocked countries (Afghanistan, Bhutan, Burundi, Ethiopia, Laos, Lesotho, Malawi, Nepal, Rwanda, Swaziland, Uganda, Zambia, and Zimbabwe). All of these countries have a long and symbiotic relationship with the Indian Ocean, both historically and economically. These countries account for roughly 33% of the world's population (2 billion).

The Andaman Sea, Arabian Sea, Arafura Sea, Lakshadweep Sea, Malagassi Sea, Red Sea, Sawu Sea, and Timor Sea make up the Indian Ocean's marginal seas. The Bay of Bengal, Great Australian Bight, Gulf of Aden, Gulf of Carpentaria, Gulf of Oman, Gulf of Martaban, Persian Gulf, and Gulf of Spencer are the Indian Ocean's principal gulfs. Bass Strait, Malacca Strait, Mozambique Channel, Palk Strait, Selat-Sunda Strait, and Tore Strait are the major straits. It has the most marginal seas-touching warm water in contrast to other oceans.

Socotra Ridge, Chagos Ridge, Gavssberg Ridge, Madagascar Ridge, Seychelles Ridge, St. Paul Ridge, 900 Ridge, Kerguelen Plateau, Prince Edward Island (Ridge), and Seychelles –Mauritius Ridge are the oceanic ridges in the Indian Ocean.