Mafia Island Diving, Tanzania: Undercurrent 04/2026

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Dear Fellow Diver,

Our dive guide, Sadiki, motioned me over and pointed to a small clump of greenery and entwined plant debris. A hidden poisonous ocellated octopus, yes, I see that. Baby lionfish, check. Oh, wait: an inch-long frogfish, perched between two leaves. The fifth one on this dive was very cool but no longer exhilarating. He pointed at a small green spot on a green leaf: a sap-sucking slug, a sacoglossam, maybe a quarter-inch long, a kleptoplast that eats tiny chloroplasts from algae to become a solar-powered slug. This was turning out to be a really great dive.

The traditional sailboat used for diving Mafia (pronounced: Mah-FEE-ah) Island, about 30 miles long and 10 miles wide, with a population 66,000, is a few miles off Dares-Salaam, Tanzania's capital. The east side hosts the Mafia Island Marine Park, a protected Indian Ocean area of over 300 square miles, with broad biodiversity and both reef and muck diving. With just three dive shops in the Park and a handful of accommodations, it's a quiet island, predominantly populated largely by the Swahili coastal culture, with a large Arab and Persian influence, and largely Muslim.

Before departing, I couldn't find reliable information to select a shop, so convenience drove my choice: Mafia Island Diving (MID) is next to the hotel Basecamp Mafia Island, about 100 meters away down a sand pathway. MID uses handcrafted local sailboats, traditional dhonis with outboards. One of the two other operators, Dive Planet, runs a modern fiberglass boat, which would have reduced the hour it took to outer dive sites -- but no one has Nitrox, so two dives a day was about all that my computer would let me do anyway.

My first clue that diving wasn't typical was when I arrived in mid-February to check in. "The tides dictate our schedule," the shop manager began, "so here's what I recommend." (Protected diving is within Chole Bay, and venturing out to see larger and more diverse fish is tide- and weather-affected.) They recorded both my C card and DAN card, and they laid out a schedule to take advantage of the best conditions. They attached little tags with strings to each piece of my gear and checked it; my first stage needed adjustment, which they did on the spot, and without a charge. That is quite the service.

Mafia Island - Map MID can handle about two dozen divers, but the most I dived with was 10, split into groups with three dive guides. On my first dive day, my buddy and I arrived 30 minutes before the departure; our gear had been rinsed and folded and put on a bench under our name, while our BCDs and regulators were attached to aluminum DIN-valve 11-liter (80 cu.ft.) or 12-liter tanks, ready for a quick check before being loaded onto the boat. We waded out -- no dive shop has a dock -- and hopped on for a 30-minute ride to two close sites inside the bay, Small Rock and Chole Reef, protected by Juani Island....

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