Zanzibar Island Hopping: Mnemba, Prison Island, and Beyond

Islands Around Zanzibar

Zanzibar's main island, Unguja, is surrounded by a constellation of smaller islands, each with a distinct character. From marine sanctuaries teeming with turtles to a private island resort to an uninhabited sandbank that appears at low tide, island hopping reveals a side of Zanzibar that beach resorts cannot. Here's your guide to each island, with practical logistics and honest cost breakdowns.

Mnemba Atoll

What it is: A small private island surrounded by a coral reef atoll 3 km off the northeast coast. The island itself is occupied by &Beyond's exclusive lodge (12 bandas, $1,500-3,000/night), but the surrounding reef is public and serves as Zanzibar's premier snorkeling and diving destination.

What you'll see: Green sea turtles are the headline — they're resident on the reef and virtually guaranteed. You'll also encounter reef sharks (blacktip, non-aggressive), schools of barracuda, blue-spotted stingrays, octopus, and hundreds of reef fish species. Dolphins are common in the deeper water around the atoll.

Logistics: Boat trips depart from Matemwe (20 min) or Nungwi (30 min). You cannot land on the island unless you're a lodge guest.

Cost: $45-60pp for a half-day snorkeling trip (3-4 hours, equipment included). Scuba diving: $80-120 per dive with equipment.

Best time: June-October and December-February for best visibility (20-30 meters). Avoid April-May when seas are rough and visibility drops.

Tips: Go early morning (depart 8:00 AM) for calmest seas and best underwater light. Bring your own mask if you have one — rental masks often leak. Reef-safe sunscreen only.

Prison Island (Changuu)

What it is: A small island 5.6 km northwest of Stone Town, originally intended as a prison for rebellious slaves but never used as one — it became a quarantine station instead. Today it's home to a colony of Aldabra giant tortoises imported from Seychelles in the late 19th century, some now exceeding 100 years old and weighing 200+ kg.

What you'll see: The tortoises are the main draw — roughly 100 roam a fenced sanctuary where you can feed them (spinach and lettuce) and take photos. Some are remarkably gentle and will eat from your hand. The island also has a small beach with reasonable snorkeling, the ruins of the quarantine buildings, and a smattering of peacocks.

Logistics: Boats depart from Stone Town waterfront (Forodhani area). The crossing takes 25-30 minutes by motorboat.

Cost: $35-50pp including boat, guide, island entry ($4), and snorkeling equipment. Private boat charters: $100-150.

Best time: Morning visits (9-11 AM) avoid midday heat. Tortoises are most active early. The snorkeling is better at high tide.

Tips: Combine with a Stone Town walking tour for a full morning. The island gets crowded with tour groups by 10:30 AM — arrive early for a quieter experience.

Chumbe Island

What it is: A coral park and marine sanctuary 12 km south of Stone Town. Chumbe Island Coral Park is a private conservation project that protects one of the most pristine coral reefs in East Africa. Only 14 guests can stay overnight (in eco-bungalows powered by solar and rainwater), but day trips are available.

What you'll see: The reef is extraordinary — over 200 species of hard coral (90% of all known coral genera in East Africa) and 400+ fish species. The marine area has been protected since 1994, and the difference from unprotected reefs is dramatic. On land, the coral rag forest shelters the rare Ader's duiker (a tiny antelope) and coconut crabs.

Logistics: Day trips depart from Mbweni (south of Stone Town) at 10:00 AM and return at 5:00 PM. Advance booking essential — limited to a few dozen visitors per day.

Cost: $100pp for the full-day guided excursion (includes boat, ranger-guided snorkeling, forest walk, and seafood lunch). Overnight stays: $280-350/person in eco-bungalows.

Best time: Year-round, but visibility is best June-October (25-40 meters). The conservation story makes this worthwhile even in lower-visibility months.

Tips: This is the most educational island experience in Zanzibar. The rangers are passionate marine biologists who explain reef ecology, coral bleaching, and conservation challenges. Worth every dollar.

Sandbank Picnics (Nakupenda and Others)

What it is: At low tide, white sand banks emerge from the turquoise shallows between Stone Town and Prison Island. Nakupenda ("I Love You" in Swahili) is the most popular — a temporary island of pure white sand surrounded by impossibly blue water.

What you'll do: Your boat drops you on the sandbank with a cooler of drinks, fresh fruit, and seafood. You swim, snorkel the surrounding shallows, sunbathe, and take the kind of photographs that make your friends jealous. Some operators set up shade tents and serve grilled lobster.

Logistics: Often combined with Prison Island — the two are 15 minutes apart by boat.

Cost: $25-40pp when combined with Prison Island. Standalone sandbank trips: $30-50pp. Private setups with lobster lunch: $100-200 for two.

Best time: Check tide charts — the sandbank only appears at low tide. Morning low tides (9-11 AM) offer the best light for photography.

Bawe Island

What it is: A small island 6 km west of Stone Town, less visited than Prison Island. Historically a staging point for the underwater telegraph cable connecting Zanzibar to mainland East Africa. Today it has a quiet beach, basic facilities, and decent snorkeling.

Cost: $30-40pp including boat and snorkeling. Often combined with Prison Island or Nakupenda for a half-day circuit.

Best for: Travelers who want a quieter island experience without the tour-group crowds of Prison Island.

Planning Your Island Hopping

Half-day combo (3-4 hours, $40-60pp): Prison Island + Nakupenda sandbank. The most popular and best-value option.

Full-day marine (6-7 hours, $80-120pp): Mnemba Atoll snorkeling + sandbank lunch. Departs from Matemwe or Nungwi.

Full-day conservation (7 hours, $100pp): Chumbe Island day trip. Book directly through Chumbe Island Coral Park.

Multi-day itinerary: Prison Island (day 1) + Mnemba Atoll (day 2) + Chumbe Island (day 3). Three different islands, three different experiences, spread across your stay.

Frequently Asked Questions

Do I need to know how to swim for island hopping?

Swimming ability helps but isn't essential. Prison Island and sandbank visits are on land with optional shallow wading. For Mnemba and Chumbe snorkeling, you should be comfortable in open water. Life jackets are provided on all boat trips, and guides assist non-confident swimmers.

Are the boats safe?

Licensed tour operators use fiberglass motorboats with life jackets, first aid kits, and experienced captains. Traditional dhows are also used for some trips — they're stable and seaworthy but slower. Always confirm that your operator is licensed and the boat carries safety equipment before boarding.

Can I visit Mnemba Island itself?

Only if you're staying at the &Beyond Mnemba Island lodge ($1,500-3,000/night). Day visitors cannot land on the island — you snorkel the surrounding reef from the boat. The reef is the attraction, not the island, so you're not missing the main experience.