1. There are 39 islands in the Indian Ocean. Most of them are away from the coastline. They are deep sea islands. 

2. The islands of the Indian Ocean are a varied collection, including many smallest territories and some large islands like Sri Lanka, Australia and Madagascar.

The islands in the Indian Ocean are grouped into-

1. Islands of Arabian sea 

2. Islands along Bay of Bengal 

3. Islands along the Australian coast

Islands in Indian Ocean-

1. Islands of the Arabian Sea can be sub grouped such as islands close to the African coast and islands along the Lakshadweep – Chagos Ridge. 

2. The largest island close to the African coast is Madagascar island. It is separated from Africa, and later from the Indo-Australian plate. It is one of the seismologically active provinces. 

3. There are many islands between the eastern coast of Africa and Madagascar island, such as Comoros, Europa and Bassas de India, etc. To the east of Madagascar are Mauritius, Reunion and Seychelles, etc. 

4. The group of islands along Lakshadweep-Chagos Ridge are Maldives, Chagos and Lakshadweep. 

5. Apart from these islands, other islands are the Bundle island near the coast of Pakistan and Siri, Lavan, Kish, Hendorabi, etc., along the Persian Gulf part of Iran.

6. The islands in Bay of Bengal are associated with the converging plate boundary. These islands are the peaks of submerged mountains. The islands of Bay of Bengal are Sri Lanka, Andaman and Nicobar group, and chain of islands along the western coast of Sumatra island of Indonesia. 

7. Most of these islands are volcanic islands. Sri Lanka is the largest island of this group. 

8. There are very few islands along the coastline of Australia such as Cacos, Christmas, Ashmore, etc.