Kalangala District covers an area of 9,103 square kilometres (3,515 sq mi), of which only 468.3 square kilometres (180.8 sq mi) (5.1%) is land and the rest is open water.

Kalangala District is bordered by Mpigi District and Waksio District to the north, Mukono District to the northeast and east, the Republic of Tanzania to the south, Rakai District to the southwest, Masak District to the west and Kalungu District to the northwest