Mombasa Island is a 5 by 3 km (3.1 by 1.9 mi) coral outcrop located on Kenya's coast on the Indian Ocean, which is connected to the mainland by a causeway.

Part of the city of Mombasa is located on the island, including the Old Town.

The old town of Mombasa is located at the eastern, seaward end of the island.

Modern residential sprawl and industrial areas now occupy the rest of the island.

Mombasa is linked to the mainland by the Makupa Causeway to the northwest, by the Nyali Bridge to the east and by the Likoni Ferry to the south.