It is located in Mwanza covering an Area of 45,700 hactares at an Altitude of 1,134 to 1,381 meters above sea level. A former Game Reserve, the National Park was established in 1977. The National Park consists of a main island, 12 much smaller islands and the expanse of water around them. These islands are situated in the south-western corner of Lake Victoria to the north of Emin Pasha Gulf. The islands are forested, with large grassy glades on the main island. The shorelines are a mix of narrow sandy beaches, rock, forest edge and isolated stands of papyrus Cyperus papyrus.

Two bird species of the Guinea - Congo Forests biome have been recorded here. The smaller islands provide safe nesting sites for bird species which would formally have bred on the nearby mainland. Ardea goliath occurs in remarkable numbers with a count of 107 birds, including 12 active nests, 638 Haliaeetusvocifer were counted within the park. This is a far higher density than has been recorded elsewhere on Lake Victoria.

Numbers of other colonial waterbirds such as Phalacrocoraxafricanus and Threskiornisaethiopicus appear here. Rubondomain island holds a wide variety of other species, including huge breeding colonies of four species of Ploceus weavers and a relatively dense population of Circaetuscinerascens which are rare in East Africa. An unidentified Batis flycatcher was recorded in forest on the main island.