The island can only be reached by boat as it has no airport; there is regular ferry service to the city of Kagoshima on the mainland.

Kodakarajima is the second southernmost inhabited island in the Tokara archipelago, and is located 73 kilometres (39 nmi) southwest from Nakanoshima and 12 kilometres (6.5 nmi) north from Takarajima.

The central peak has a height of 102 metres (335 ft) above sea level.

There is a hot spring, Yudomari-onsen on the island, with water temperatures reaching 90 deg C. The island is surrounded by a coral reef, and has a number of limestone pinnacles on its coastline.

The local climate is classified as subtropical, with a rainy season from May through September.