The Ōsumi Islands are of volcanic origin and have a total area of approximately 1,030 square kilometres (400 sq mi).

Some of the islands in the archipelago have local legends of providing refuge to the Heike clan after their defeat in the Genpei War at the end of the Heian period.

During the Sengoku period, in 1543 a Chinese vessel with the Portuguese Fernão Mendes Pinto stranded on Tanegashima and is credited with introducing firearms to Japan.

In fact, Pinto was probably not present at the first Portuguese contact with the Japanese, although he did visit Tanegashima soon after and legend says he did marry a local woman and had a son.

During The Battle of Okinawa in 1945, the Ōsumi Islands were subject to aerial bombardment by U.S. Navy and U.S. Army Air Force aircraft.