Critter's Alley is a muck and reef dive site located just off the shore of Mafia Island, Tanzania. Situated at the edge of a drop-off, the site features a sandy bottom interspersed with patches of weed and small bommies. Divers typically explore this area at depths between 7 and 10 metres, with an average depth of 8 metres. The site is suitable for beginners and experiences mild currents. Visibility ranges from 10 to 30 metres, and water temperatures fluctuate between 26C and 30C throughout the year. Shore access is available, and the site supports night diving. Hazards include sea urchins and sharp coral.

Dive Planet Mafia Island features a diverse underwater topography consisting of reef slopes, walls, and drift sections. Depths range from 5 to 30 metres, with an average of 14 metres, making it suitable for both beginners and experienced divers. Visibility varies between 8 and 30 metres, and water temperatures remain warm, ranging from 26 to 30 degrees Celsius. Entry is possible from both shore and boat. The site is also available for night dives. Divers should be aware of moderate currents that can surge, as well as boat traffic. Facilities at the site include equipment rental, air fills, and guided tours.

Frogfish Town on Mafia Island is a reef and cave system reaching depths of 12 metres. The reef structure begins at approximately 9 metres, featuring a topography dominated by algae, soft corals, sponges, and anemones. To the east, the site transitions into a more varied landscape characterised by small caverns and rock pinnacles. Conditions are generally mild, making this location suitable for beginner divers. Access is available via both shore and boat entries. Divers should remain aware of potential boat traffic in the area. Water temperatures remain warm throughout the year, ranging between 26C and 30C.

Nudi City is a reef and muck dive site located 300 metres off Utende beach on Mafia Island. With an average depth of 9 metres, the site is suitable for beginners and offers both shore and boat access. Divers typically experience mild currents and visibility ranging from 10 to 30 metres. The topography features soft corals and anemones, providing a habitat for juvenile fish, scorpion fish, dwarf lion fish, and various macro life including shrimps and flatworms. Water temperatures remain between 26 and 30C, with a thermocline present at approximately 12 metres. Night diving is available at this location, with typical dives lasting 45 minutes.

Danii's Reef is a diverse site featuring both reef and muck environments, reaching a maximum depth of 16 metres. The topography transitions from shallow bommies and soft coral fields to mini walls and overhangs in the north. Divers can explore areas containing sunken pots and ceramic shards from historical merchant vessels. The site is accessible only by boat and is suitable for beginners, though divers should be aware of potential entanglement hazards, sharp coral, and mild currents. Visibility typically ranges between 15 and 30 metres, with water temperatures remaining between 26 and 30C throughout the year.

Milimani South is a reef site located off Mafia Island, Tanzania, characterised by ancient hard coral formations that rise from depths of 22 metres to near the surface. This site is suitable for beginners and features mild currents. Access is by boat only. Divers should be aware of boat traffic and depth as potential hazards. Water temperatures range from 26C to 30C throughout the year. While specific sightings at this exact site are not confirmed, species recorded around this area include peacock mantis shrimp, nudibranchs, flatworms, pufferfish, and various butterflyfish and wrasse species.

Jina Reef off Mafia Island is a dynamic site featuring a combination of reef structures and a wall. Divers experience drift diving at depths ranging from 8 to 26 metres, with an average depth of 17 metres. Visibility is variable, typically between 15 and 40 metres. Due to moderate currents, this site is suited for intermediate divers with strong buoyancy control. Access is by boat only, and divers must be self-sufficient as facilities are not available on-site. Hazards include sharp coral and currents that can vary in strength, requiring close attention to guide instructions and positioning throughout the dive.

Kitutia Reef is a shallow marine site located off Mafia Island, Tanzania, offering depths between 5 and 15 metres with an average of 8 metres. Access is exclusively by boat. The site features moderate currents that can strengthen, requiring divers to remain close to their guide and exercise caution around sharp coral structures. Visibility is variable, ranging from 8 to 30 metres. Water temperatures typically range from 26 to 30 degrees Celsius, though thermoclines as low as 24 degrees Celsius may occur between June and September. This site is suitable for beginner divers, provided they confirm tide timings with their operator due to potential current fluctuations.