The island is the third largest in Tanzanian ocean territory,[1] but is not administratively included within the semi-autonomous region of Zanzibar, which has been politically separate since 1890.

The island attracts some tourists, mainly scuba divers, birdwatchers, game fishermen, and people seeking relaxation.

[7][8] Mafia Island, (394 km2 (152 sq mi)), lies off the east coast of Tanzania opposite the delta of the Rufiji River.

[1] A 115,000 ha area, encompassing Chole Bay, the southern coastline of Mafia and its associated smaller islands, along with the intervening marine waters, has been designated an Important Bird Area (IBA) by BirdLife International because it supports populations of western reef egrets, Terek sandpipers and crab plovers.

[13] In the mid-1820s, the town of Kua on Juani Island was attacked by Sakalava cannibals arriving from Madagascar with 80 canoes, who ate many of the locals and took the rest into slavery.

Germany paid Sultan Sayyid Ali bin Said al-Said of Zanzibar M4 million for both the island and part of the mainland coast.

The organization continued to provide support to the Island under Rufiji-Mafia-Kilwa (RUMAKI)[15] seascape project to improve socio-economic well-being of the communities through the sustainable, participatory and equitable utilization and protection of their natural resources.

Under the current EU-WWF Fisheries Co-management Project,[16] the organization aims at building effective long-term fisheries co-management through establishment of 10 Beach Management Units and to continue supporting Village Community Banks (VICOBA) in the Island to generate optimal, sustainable and equitable livelihood benefits, and which provide a source of lesson-learning for other coastal communities.

Tanzania's first multi-user marine park at Mafia Island was established in 1995 following management recommendations and data from surveys conducted by the Society for Environmental Exploration.