
Anjouan is an autonomous high island in the Indian Ocean that forms part of the Union of the Comoros. Its chief town is Mutsamudu and, as of 2006, its population is around 277,500. The total area of the island is 424 square kilometers.

The Australian Indian Ocean Territories is the name since 1995 of an administrative unit under the Australian Department of Infrastructure, Transport, Cities and Regional Development, consisting of two islands groups in the Indian Ocean under Australian sovereignty:Christmas Island, where the administrator resides Cocos (Keeling) Islands, where the same officer also has jurisdiction as administrator but does not reside

The British Indian Ocean Territory (BIOT) is a British overseas territory of the United Kingdom situated in the Indian Ocean halfway between Tanzania and Indonesia. The territory comprises the seven atolls of the Chagos Archipelago with over 1,000 individual islands – many very small – amounting to a total land area of 60 square kilometres (23 sq mi). The largest and most southerly island is Diego Garcia, 27 km2 (10 sq mi), the site of a joint military facility of the United Kingdom and the United States.

The Territory of Christmas Island is an Australian external territory comprising the island of the same name. Christmas Island is located in the Indian Ocean, around 350 kilometres (220 mi) south of Java and Sumatra and around 1,550 kilometres (960 mi) north-west of the closest point on the Australian mainland. It has an area of 135 square kilometres (52 sq mi).

The Territory of Cocos (Keeling) Islands is an Australian external territory in the Indian Ocean, comprising a small archipelago approximately midway between Australia and Sri Lanka. It is part of Southeast Asia and is in the Southern Hemisphere. The territory's dual name reflects that the islands have historically been known as either the Cocos Islands or the Keeling Islands.

The Comoros, officially the Union of the Comoros, is an island country in the Indian Ocean located at the northern end of the Mozambique Channel off the eastern coast of Africa. It shares maritime borders with Madagascar and the French region of Mayotte to the southeast, Tanzania to the northwest, Mozambique to the west, and the Seychelles to the northeast. The capital and largest city in Comoros is Moroni. In addition, the religion of the majority of the population, and the official state religion, is Sunni Islam. As a member of the Arab League, the Comoros is the only country in the Arab world which is entirely in the Southern Hemisphere. It is also a member state of the African Union, the Organisation internationale de la Francophonie, the Organisation of Islamic Cooperation, and the Indian Ocean Commission. Furthermore, the Union of the Comoros has three official languages—Comorian, French, and Arabic.

Mauritius was an official settlement of the Dutch East India Company on the island of Mauritius between 1638 and 1710, and used as a refreshing station for passing ships. It was already frequented by Dutch ships from 1598 onwards, but only settled in 1638, to prevent the French and the British from settling on the island.

East Timor or Timor-Leste, officially the Democratic Republic of Timor-Leste, is an island country in Southeast Asia. It comprises the eastern half of the island of Timor, the nearby islands of Atauro and Jaco, and Oecusse, an exclave on the northwestern side of the island surrounded by Indonesian West Timor. Australia is the country's southern neighbour, separated by the Timor Sea. The country's size is about 15,007 km2.

The French Southern and Antarctic Lands is an Overseas Territory of France. It consists of:Adélie Land, the French claim on the continent of Antarctica. Crozet Islands, a group in the southern Indian Ocean, south of Madagascar. Kerguelen Islands, a group of volcanic islands in the southern Indian Ocean, southeast of Africa, approximately equidistant between Africa, Antarctica and Australia. Saint Paul and Amsterdam Islands, a group to the north of the Kerguelen Islands. The Scattered Islands, a dispersed group of islands around the coast of Madagascar.

Isle de France was the name of the Indian Ocean island which is known as Mauritius and its dependent territories between 1715 and 1810, when the area was under the French East India Company and part of France's empire. Under the French, the island witnessed major changes. The increasing importance of agriculture led to the importation of slaves and the undertaking of vast infrastructural works that transformed Port Louis into a major capital, port, warehousing, and commercial centre.

Madagascar, officially the Republic of Madagascar, and previously known as the Malagasy Republic, is an island country in the Indian Ocean, approximately 400 kilometres off the coast of East Africa. At 592,800 square kilometres (228,900 sq mi) Madagascar is the world's second-largest island country. The nation comprises the island of Madagascar and numerous smaller peripheral islands. Following the prehistoric breakup of the supercontinent Gondwana, Madagascar split from the Indian subcontinent around 88 million years ago, allowing native plants and animals to evolve in relative isolation. Consequently, Madagascar is a biodiversity hotspot; over 90% of its wildlife is found nowhere else on Earth. The island's diverse ecosystems and unique wildlife are threatened by the encroachment of the rapidly growing human population and other environmental threats.

Maldives, officially the Republic of Maldives, is a small archipelagic island country in South Asia, situated in the Arabian Sea of the Indian Ocean. It lies southwest of Sri Lanka and India, about 700 kilometres (430 mi) from the Asian continent's mainland. The chain of 26 atolls stretches from Ihavandhippolhu Atoll in the north to Addu Atoll in the south. Comprising a territory spanning roughly 298 square kilometres (115 sq mi), the Maldives is one of the world's most geographically dispersed sovereign states as well as the smallest Asian country by land area and population, with around 515,696 inhabitants. Malé is the capital and the most populated city, traditionally called the "King's Island" where the ancient royal dynasties ruled for its central location.

Mauritius, officially the Republic of Mauritius, is an island nation in the Indian Ocean about 2,000 kilometres (1,200 mi) off the southeast coast of the African continent, east of Madagascar. It includes the eponymous main island of Mauritius and Rodrigues, Agaléga and St. Brandon. The islands of Mauritius and Rodrigues form part of the Mascarene Islands, along with nearby Réunion, a French overseas department. The capital and largest city, Port Louis, is located on Mauritius, where most of the population is concentrated. The country spans 2,040 square kilometres (790 sq mi) and has an Exclusive Economic Zone covering 2.3 million square kilometres.

Mayotte is an overseas department and region of France officially named the Department of Mayotte. It consists of a main island, Grande-Terre, a smaller island, Petite-Terre, and several islets around these two. Mayotte is part of the Comoros archipelago, located in the northern Mozambique Channel in the Indian Ocean off the coast of Southeast Africa, between northwestern Madagascar and northeastern Mozambique. The department status of Mayotte is recent and the region remains, by a significant margin, the poorest in France. Mayotte is nevertheless much more prosperous than the other countries of the Mozambique Channel, making it a major destination for illegal immigration.

Mohéli [mɔ.e.li], also known as Mwali, is an autonomous island that forms part of the Union of the Comoros. It is the smallest of the three major islands in the country.

Réunion is an overseas department and region of the French Republic and an Indian Ocean island in East Africa, east of Madagascar and 175 km (109 mi) southwest of Mauritius. As of January 2020, it had a population of 859,959.

The Scattered Islands in the Indian Ocean consist of four small coral islands, an atoll, and a reef in the Indian Ocean, and have constituted the 5th district of the French Southern and Antarctic Lands (TAAF), though sovereignty over some or all of the Islands is contested by Madagascar, Mauritius, and the Comoros. None of the islands has ever had a permanent population.

Seychelles, officially the Republic of Seychelles, is an archipelagic island country in the Indian Ocean at the eastern edge of the Somali Sea. The country consists of 115 islands. Its capital and largest city, Victoria, lies 1,500 kilometres (932 mi) east of mainland Africa. Other nearby island countries and territories include the Comoros, Madagascar, Mauritius, and the French overseas regions of Mayotte and Réunion to the south; as well as Maldives and the Chagos Archipelago to the east. With a population of roughly 98,462 , it has the smallest population of any sovereign African country.

Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is an island country in South Asia, located in the Indian Ocean southwest of the Bay of Bengal and southeast of the Arabian Sea. Sri Lanka has been called “the pearl of the Indian ocean” because of its shape and location. It is geographically separated from the Indian subcontinent by the Gulf of Mannar and the Palk Strait. Sri Jayawardenepura Kotte is its legislative capital, and Colombo is its largest city and centre of commerce.

The Sultanate of Zanzibar, also known as the Zanzibar Sultanate, was an Islamic state controlled by the Sultan of Zanzibar, in place between 1856 and 1964. The Sultanate's territories varied over time, and at their greatest extent spanned all of present-day Kenya and the Zanzibar Archipelago of the Swahili Coast. After a decline, the state controlled only Zanzibar and a 16-kilometre-wide (10 mi) strip along the Kenyan coast, with the interior of Kenya controlled by the British Kenya Colony.

The United Suvadive Republic or Suvadive Islands was a short-lived breakaway nation in the remote southern atolls of the Maldive Islands that constitute the Suvadive archipelago.