This is the experience that has put Mafia on the map. From around October to March the island becomes one of the very best places on earth to snorkel alongside whale sharks — the largest fish in the ocean, reaching up to eighteen metres, and utterly harmless filter-feeders that cruise the surface gulping plankton. The remarkable thing about Mafia is that they feed in the shallows right off the island, just five to ten minutes by boat from Kilindoni.

You slip quietly into the water and swim beside these gentle giants — an awe-inspiring, slightly humbling encounter that people travel across the world for.

It is done strictly by snorkel and to a code of conduct: look, never touch, and keep a respectful distance, which the good operators we use enforce. Be clear it is seasonal — roughly October to March — and weather-dependent, and that, as with all wild animals, sightings are likely in season but never guaranteed. Confident swimmers will love it. We arrange a responsible trip. Pricing on request.

At the heart of Mafia’s appeal is the Mafia Island Marine Park, established in 1995 as the very first marine park in Tanzania and still one of the most important conservation areas in the Indian Ocean. It protects much of the island’s shoreline, centred on the sheltered Chole Bay, and the protection shows: the reefs here are exceptionally healthy, home to well over four hundred species of fish, five species of turtle, vivid hard and soft corals, and the rare, elusive dugong for which the bay is a critical refuge.

For snorkelers it is a dream — a dhow ride out to a reef site and a drift over coral gardens teeming with colour — and migrating humpback whales even pass offshore between August and October.

A daily marine park conservation fee applies, which goes directly to protecting all this, and snorkelling times shift with the tides, so we plan around them. Wonderful for all ages. We arrange the trips and fees. Pricing on request.

Mafia is regarded as one of the finest diving destinations in East Africa, and the protected, current-fed reefs deliver world-class underwater life. There are around twenty dive sites split between two worlds: the thirteen inside sheltered Chole Bay are mostly shallow, gentle sloping reefs and coral gardens, perfect for beginners and courses, while the eight outside the bay are deeper, with dramatic walls, channels and drift dives that bring in the bigger stuff — ideal for experienced divers.

Whichever you dive, the cast is superb: green turtles, reef sharks, moray eels, rays, groupers and hundreds of reef-fish species over healthy, living coral.

A seasonal note worth planning around: the best all-sites diving runs October to March, while from June to September the winds usually confine diving to inside the bay, and in the April-May rains many lodges close. Beginners and old hands are both well served. We arrange the dive centre and courses. Pricing on request.

A little further out, Juani Island rewards the effort of reaching it (a dhow ride and a walk) with two quite different treasures. The first is history: the ruins of Kua, a medieval Swahili-Arabic city dating back some eight hundred years, with mosques, residences and a sultan’s palace now lost in the forest — a town abandoned after a devastating raid from Madagascar in the 1820s, and gloriously atmospheric today. Around it lie mangrove forests, birdlife and the odd monkey.

The second is turtles. Juani’s quiet beaches are a green-turtle nesting site, and between roughly June and September a conservation project lets visitors witness the hatchlings emerging and racing for the sea — a fragile, magical moment.

One key planning note: the turtle season (June to September) is the opposite of the whale-shark season (October to March), so you will likely catch one or the other, not both. We time the visit. Pricing on request.

If your idea of paradise is a beach with no one else on it, Mafia delivers. Where Zanzibar’s sands can hum with resorts and crowds, Mafia’s are quiet, undeveloped and often empty — long stretches of pale sand backed by palms and a scattering of small lodges, with the space and silence that the bigger islands lost long ago.

It is tailor-made for honeymooners, for anyone craving genuine tranquility, and for photographers after that empty-beach shot.

Set your expectations rightly and you will love it: this is undeveloped island simplicity, not a resort strip, and as on any ocean coast the tides shape when and where you swim. For peace and privacy it is hard to beat. We match you to the right beach and lodge. Pricing on request.

The timeless way to enjoy Mafia’s waters is aboard a dhow, the traditional lateen-sailed Swahili boat. A sunset cruise — drifting across Chole Bay as the sky turns and the light softens on the water — is the romantic classic, often with a drink and the day’s catch aboard.

By day, the dhows make for the sandbanks: dazzling spits of white sand that rise from the turquoise shallows, where you are dropped for a few blissful hours of swimming, snorkelling and a picnic lunch on what feels like your own private beach in the middle of the ocean.

Both depend a little on wind and tide — the sandbanks come and go with the water, and a dhow may sail or motor — but either way it is a beautiful few hours afloat. Lovely for couples and families alike. We arrange the dhow and the sandbank trip. Pricing on request.

Most visitors land at Kilindoni, Mafia’s main town, and it is worth more than a passing glance. This bustling little fishing port is the island’s beating heart — boats coming and going, a lively market piled with fresh produce and the day’s catch, and the everyday rhythm of Swahili island life going on much as it always has.

It is the place to feel the real Mafia: wander the market, watch the fishing fleet, meet the community, and eat superbly fresh seafood at a simple local restaurant.

It is an unpolished working town rather than a sight in the usual sense — which is exactly its appeal — and it is also where the whale-shark boats set out, so many visitors pass through anyway. A genuine, characterful stop. We can include a guided wander. Pricing on request.