2633+ Reviews on TripAdvisor

Prison Island, Zanzibar

Twenty minutes off Stone Town sits an island built for detention, better known as a quarantine station, and home to a colony of century-old giant tortoises.

Aerial view of a Zanzibar beach town, white sand and reef water
Guide
Culture
Reading time
5minutes
In this guide
4sections
  • Half day
  • 20-min boat
  • Aldabra tortoises

Written and maintained by the Safari Soles planning team in Arusha, Tanzania.

Add a half-day trip

Changuu, universally called Prison Island, is a twenty-minute boat ride from Stone Town.

  1. Best as a half day from Stone Town, not from a distant beach hotel.
  2. Morning boats are calmer; afternoons can be choppy.
  3. Bring cash in small notes for the entry fee.
  4. Snorkel gear is worth taking; the reef off the beach is decent.
  5. Combine with the Stone Town sunset rather than a full beach day.
Ask us to plan this

Prepared by Gibson Philip, Safari Soles · Last verified 2 September 2026

01 / 04

Built for detention, better known for quarantine

Changuu was used in 1860s Zanzibar as a holding point connected to the slave trade, and later transferred to the British, who in the 1890s built a complex intended for detention. Accounts of what happened next differ in detail, but the island is not recorded as having operated as a working convict prison. By the time the buildings were finished, the more pressing problem was yellow fever and cholera arriving by ship, so the buildings became a quarantine station where arriving passengers were held for observation before entering Zanzibar.

The coral-rag buildings still stand, roofless in places, and you can walk through them freely. There is no elaborate museum (a few interpretive boards and the structures themselves), which is either refreshingly unvarnished or slightly thin depending on your temperament.

02 / 04

The Aldabra giant tortoise sanctuary

In 1919 the British governor of the Seychelles sent four Aldabra giant tortoises to Zanzibar as a gift. Their descendants, and imports since, now number well over a hundred, living in a fenced sanctuary on the island. The oldest are marked with their year of hatching painted on the shell; several are over 150 years old, which means they were alive when the quarantine station was built.

They are enormous, slow and entirely unbothered by people. You can walk among them, feed them spinach leaves handed out at the gate, and (this is the part children remember) scratch the underside of a neck the size of your forearm while the animal stretches out and closes its eyes. The colony is managed, the animals are in good condition, and the entry fee funds their care.

  • Feed only the greens provided at the sanctuary gate.
  • Do not sit or climb on the tortoises, however much a guide encourages it.
  • Wash your hands afterwards; reptiles carry salmonella.
  • The painted numbers are hatch years, not ages.
  • Entry fee is separate from your boat fare: carry small US dollars or shillings.

03 / 04

Boats, fees and timing

Departure point
Forodhani seafront, Stone Town
Crossing time
About 20 minutes each way
Shared boat
Roughly US$25–40 per person including guide
Private boat
Better for families; negotiated by boat, not per head
Island entry
About US$4–5 per adult, paid on arrival
Total time
3–4 hours door to door
Best departure
Morning, when the channel is calmest

Book through your hotel or a proper operator rather than from someone on the seafront. The difference is a boat with lifejackets and a guide who explains what you are looking at, versus an unlicensed skiff. The channel is short but it is open water and it gets choppy in the afternoon, particularly during the Kusi winds from June to September. Our Zanzibar travel guide covers how a half day like this fits the wider trip.

There is a small beach with loungers, a bar and a shallow house reef where snorkelling is reasonable: nothing like Mnemba, but pleasant enough to justify bringing a mask. Some operators combine Changuu with Nakupenda sandbank for a longer day, which is a better use of a boat if you have the time. Our ocean activity guide covers the other options.

04 / 04

Changuu: built for detention, used for quarantine

Prison Island is a nickname, and a partial one. The island's proper name is Changuu, and the complex built there in the 1890s was intended for detention but is not recorded as having held convicts in that role. It was repurposed as a quarantine station for yellow fever and other diseases, which is what it functioned as for decades: a role that says a good deal about the shipping traffic passing through Zanzibar at the time.

The darker part of the island's history is earlier and less visible. Before the prison was built, Changuu was used in connection with the slave trade as a holding point, in the period when Zanzibar was the major slaving entrepôt of the East African coast. The guides on the island vary in how fully they cover this; a good one will. The Stone Town guide covers the trade and its abolition in depth.

The tortoises came later still. The founding group of Aldabra giant tortoises was a gift from the Seychelles in the late nineteenth century, and the population on the island today descends from them. Some individuals are genuinely old, with recorded ages well past a century, and their approximate birth years are marked on their shells.

Visiting well

  • Boat from Stone Town takes roughly 20 to 30 minutes; go early to avoid the mid-morning crowd and the heat.
  • Entry fee is charged on the island in addition to the boat, and includes the tortoise sanctuary.
  • Touch the tortoises gently or not at all, do not sit on them, do not feed anything other than the greens sold on site, and wash your hands after.
  • Bring reef shoes and a snorkel: the small beach and reef on the island's north side are pleasant when the boat crowd has moved on.
  • Half a day maximum. Changuu is a good morning, not a full one. Combine it with the Stone Town waterfront or the Forodhani gardens in the evening.
  • Check the sea state in the windier kusi months; the crossing is short but can be bumpy.

Common mistakes to avoid

The planning slips we see most often. Each one is easy to avoid once you know it.

  1. Booking it as a full-day trip from a north or east coast hotel. It is a Stone Town half day.
  2. Taking an unlicensed boat off the seafront with no lifejackets.
  3. Arriving without small notes for the entry fee.
  4. Expecting a major museum; the ruins are unrestored.
  5. Going in the afternoon during the windy months and getting a rough crossing.
Safari Soles planning note

Changuu is a good two hours, not a great day. We book it as a morning from Stone Town, usually on your arrival or departure day, and steer people towards Mnemba or a sandbank trip if what they actually want is snorkelling. It pairs naturally with a Forodhani evening, covered in our island food guide, and we can build a custom safari around a Stone Town half day if that suits your trip better.

Questions worth asking any operator

Copy these questions into your enquiry: to us or to any operator you are comparing. The answers tell you more about a Zanzibar trip than any brochure.

  1. Is the boat licensed and does it carry lifejackets?
  2. Is the island entry fee included?
  3. Is the boat private or shared, and with how many?
  4. Is snorkel gear provided?
  5. What time do we leave: morning or afternoon?

What Safari Soles puts in writing

Nothing important about your trip should be discovered at check-in. Each of these is put in writing for your itinerary before you pay a deposit.

  • Which beach area, and why that one for our dates?

    Tide, wind and atmosphere vary hugely by coast; the reason should match how you want to spend your days.

  • What exactly is included in the board basis?

    Half board, full board and all-inclusive mean different things island to island: drinks and excursions are often outside.

  • How are transfers and internal flights handled?

    Baggage limits, drive times and connection buffers decide whether a safari-to-beach day is calm or stressful.

  • Which excursions are booked, and at what price?

    Pre-booked trips at fixed prices avoid beach-side selling and surprise costs mid-holiday.

  • What is the payment, change and cancellation policy?

    Island hotels have their own terms; you should see them in writing before you pay a deposit.

How we run a Zanzibar trip

Safari Soles is a Tanzania-based team. This is what we do for every traveller who books an island stay with us, in plain language.

  • One planner, start to finish

    The person who plans your route is the person who answers on the day you travel. No handover to an unnamed inbox.

  • Itemised quotes

    Accommodation, transfers, flights, excursions and fees are listed separately so you can see exactly what you are paying for.

  • Safari and beach as one trip

    We plan the parks, the internal flight and the island days together, which is where most Zanzibar itineraries go wrong.

  • Honest seasonal advice

    If your dates fall in the long rains or a tide window that will not suit you, we say so and suggest an alternative.

Planned by people who live the route

This hub exists because the same Zanzibar questions come up on every safari enquiry we answer.

  • Locally based in Tanzania
  • Safari and island specialists
  • Licensed and insured operator
  • Fast, direct answers
Where these facts come from (2)

Related Safari Soles guides

Continue with the guides travellers usually read next.

Zanzibar Travel Guide Best beaches in Zanzibar Safari and beach Zanzibar honeymoon Stone Town Contact a local Safari Soles planner

Frequently Asked Questions

  • As a half day from Stone Town, yes. The giant tortoise colony is genuinely memorable and the ruins are interesting. It is not worth a long trip from a distant beach hotel.

A good half day off Stone Town

We will book a licensed boat, a morning departure and a guide who knows the island's real history.

Plan my Zanzibar trip Ask a local expert Chat on WhatsApp