Mafia Island sits in the Indian Ocean within Tanzania's first marine national park, and that protected status shapes everything about diving here. Sites span reef slopes, walls, drift channels, muck flats, and cave systems, all within a depth range that suits beginners through to intermediate divers. The warm water, which peaks in late summer and cools slightly mid-year, hosts an unusually rich macro community: robust ghost pipefish, leaf scorpionfish, peacock mantis shrimp, and a wide range of nudibranchs appear across sites with names like Nudi City and Frogfish Town. Whale sharks visit seasonally, and diving is tide-dependent, so departure times shift daily. Conditions are best from October to March, with the rainy season reducing visibility.
Monthly water temperature across Mafia Island's sites, from satellite sea-surface data corrected for depth. The band shows the site-to-site spread.
Water temperature is warmest from late February through April and coolest between mid-year and early October, when a light wetsuit is comfortable. The dry season, broadly October to March, brings the clearest conditions and the most reliable diving, while the April to May rains can close some operations and reduce visibility noticeably.
Water temperature around Mafia Island ranges from about 26°C in July to 30°C in March, based on satellite sea-temperature data for its dive sites.
In the warm season (about 30°C) a rash guard or 3mm shorty is comfortable in Mafia Island; in the coldest months (about 26°C) step up to a 3mm full suit.
Fin maps 9 sites in Mafia Island (9 scuba diving sites and 1 snorkelling spots, with some suited to both).
Across Mafia Island's dive sites, March and October are most often reported as the best months to visit.
3 more sites to explore
