Snorkeling Tours ZanzibarPrison Island, Zanzibar: The Prison That Never Held Anyone
By Salim Haji · Zanzibar-based snorkeling guide · Updated August 2026
Prison Island Zanzibar is the easiest half day out of Stone Town and the most misnamed place on the archipelago. The British finished a prison here in 1894 and never put a single prisoner in it. What you actually cross the channel for is a colony of Aldabra giant tortoises, a set of coral-rag ruins going green under the trees, and a short snorkel stop that nobody should build a day around. If the reef is the point of your trip, start instead with the Zanzibar snorkeling tours that go to real coral.
Quick answer
Prison Island, properly Changuu, sits 5.6 km northwest of Stone Town and takes 20 to 30 minutes by boat. The draw is the Aldabra giant tortoise colony, not the reef. A private boat runs $20 to $40 return for up to about ten people, plus island entry and the marine conservation fee at the jetty.
Key takeaways
- No prisoner was ever held here. The 1894 prison became a yellow fever quarantine station instead
- The Aldabra giant tortoises were a gift from the British governor of the Seychelles, and some are over 100 years old
- Boat: 20 to 30 minutes from Stone Town, $20 to $40 return for the whole boat, not per person
- Fees change and sources disagree. Budget $15 to $25 per person for entry plus the Changuu-Bawe conservation fee, and confirm the total at the jetty
- Snorkeling here is a short hop offshore over a small patch of coral, with current. Treat it as a bonus
- Combine it: the Stone Town, Prison Island and Nakupenda day runs $68 with fees included and adds a sandbank
The Organised Way to Do It
Arranging a boat yourself at Forodhani works and costs less. This is the version that includes the old town, the crossing, the tortoises, a snorkel stop and lunch on the Nakupenda sandbank without you negotiating anything.
from $68Stone Town + Sandbank Zanzibar Stone Town Tour, Prison Island & Nakupenda with BBQ
- Guided walk through Stone Town's markets and heritage streets
- Prison Island and its Aldabra giant tortoise sanctuary
- Snorkeling stop and hours on the Nakupenda sandbank
- Seafood BBQ lunch with a vegetarian and vegan option on request
Changuu, End to End
The History Nobody Gets Right
Changuu is also called Kibandiko, and Quarantine Island, and Prison Island. Only one of those names describes something that happened.
From the 1860s the sultans used the island to hold enslaved people who had rebelled. In 1893 Lloyd Mathews, the British First Minister of Zanzibar, bought the island and began building a prison complex, finished in 1894. No prisoner was ever housed in it. Instead the buildings became a quarantine station for yellow fever cases, occupied for roughly half of each year, and a holiday spot the rest of the time.
The island was also mined for coral rag, the fossil coral that most of Stone Town is built from. Today it is a government-owned tourist site, and the prison you photograph is a building that never did the job it was built for.
The Tortoises
The Aldabra giant tortoises are the reason the boats keep coming. They arrived as a gift from the British governor of the Seychelles in the nineteenth century, and the colony has been here since. Some individuals are over a hundred years old, and their shells carry painted year markings.
You can walk among them, feed them the greens sold at the gate, and photograph them at close range. The enclosure is fenced but open to visitors, and the animals are entirely used to people. This is the part of the day children remember.
It is also the part that gets crowded. Cruise-ship groups arrive in the morning and fill the sanctuary. Afternoons are noticeably calmer.
What the Island Costs
This is the one figure I will not state as fact, because the sources genuinely disagree and it has been moving.
Island entry has been quoted at $4 per person for years, and there are traveller reports of it rising to $15. Separately, the conservation fee for the Changuu-Bawe marine area went from $3 to $10 per non-EAC adult per day on 1 September 2025, alongside the other Zanzibar marine areas.
So the honest answer in August 2026 is: budget $15 to $25 per person for entry plus conservation, carry small dollar notes, and confirm the total at the jetty before you board. Guides who quote you one clean number for everything are either including it in a package price or guessing.
| Item | Cost | Notes |
|---|---|---|
| Private boat, return | $20–$40 per boat | Up to about 10 people, negotiated at Forodhani |
| Island entry | $4, reports of $15 | Confirm at the jetty |
| Changuu-Bawe conservation fee | $10 per adult per day | Raised from $3 on 1 Sep 2025 |
| Snorkel gear rental | About $2 | Bring your own mask if you have one |
| Organised day with lunch | $68 per person | Fees included, adds Stone Town and Nakupenda |
The Snorkeling, Honestly
The boat takes you a short way off the shore and you drop into deeper water over a small area of coral. On a calm day it is pleasant. When the current runs, and it often does in the channel, it is work.
Compared with what is available elsewhere in Zanzibar this is a modest reef. Mnemba, Tumbatu and Chumbe are all in a different category, and if snorkeling is the reason for your day, none of them is Changuu. Come here for the tortoises, the ruins and a swim off the small sandy beach, and treat the mask as something to do between them.
The wooden jetty running out over the water is the photograph everyone takes, and it is worth the walk to the end and the look back.
Getting There and How Long to Stay
Boats leave from the Stone Town waterfront near Forodhani Gardens. The crossing is 20 to 30 minutes and the sea can be choppy. There is no fixed timetable: you negotiate a boat, agree a pickup time, and it waits for you.
Most visitors need two to three hours on the island. That covers the tortoises, the ruins, the jetty and the beach without rushing. Anyone building a full day usually chains it with the Nakupenda sandbank, which appears at low tide a short run further out and is where the seafood barbecue happens.
- Go in the afternoon if you can, once the cruise groups have gone
- Agree the boat price, the wait and the return time before you get in
- Carry cash in small notes for the gate and the greens for the tortoises
- Bring a hat and water. Shade on the island is patchy and the crossing is open
- Wear something you can walk the ruins in, not just flip-flops
Changuu and the Stone Town Islands
Prison Island sits with three neighbours in the channel off Stone Town.
Prison Island Zanzibar: Questions Travellers Ask
Is Prison Island worth visiting in Zanzibar?
Yes, as a half day from Stone Town, and mainly for the tortoises. The Aldabra colony is genuinely impressive, the ruins and the jetty are worth an hour, and the crossing is short. It is not worth the trip for the snorkeling, which is a small patch of coral with current. If you are based on the north coast, ninety minutes each way to see it is a stretch unless you are combining it with Stone Town anyway.
Why is it called Prison Island, Zanzibar?
Because a prison was built there, not because it was used. The island held enslaved people who had rebelled from the 1860s, and in 1893 Lloyd Mathews bought it and completed a prison complex in 1894. No prisoner was ever housed in it. The buildings served as a yellow fever quarantine station instead, which is why the island is also called Quarantine Island.
How much does it cost to visit Prison Island in Zanzibar?
A private boat runs $20 to $40 return for the whole boat, taking up to about ten people, negotiated on the Stone Town waterfront. Island entry has long been $4 per person with reports of a rise to $15, and the Changuu-Bawe conservation fee went from $3 to $10 per non-EAC adult per day on 1 September 2025. Budget $15 to $25 per person on top of the boat and confirm at the jetty. An organised day including Stone Town, the crossing, a snorkel stop, the Nakupenda sandbank and a seafood barbecue runs $68 with fees included.
Are there giant tortoises on Prison Island, Zanzibar?
Yes. The island holds a colony of endangered Aldabra giant tortoises, originally a gift from the British governor of the Seychelles in the nineteenth century. Some are over a hundred years old, their shells are marked with year numbers, and visitors can walk among them and feed them greens bought at the gate.
Can you snorkel at Prison Island?
Yes, but manage the expectation. The boat drops you a short way offshore over a small area of coral, and the current in the channel is often strong. It is a bonus on a day built around the tortoises and the ruins. For real reef, the Mnemba conservation area, Tumbatu and Chumbe are all better, and all of them need a different boat.
How long do you need on Prison Island?
Two to three hours covers the tortoise sanctuary, the prison ruins, the wooden jetty and the small beach without hurrying. Go in the afternoon if you have the choice, because cruise-ship groups fill the sanctuary in the morning. Anyone making a full day of it adds the Nakupenda sandbank, which surfaces at low tide nearby.
Want Stone Town, the tortoises and the sandbank in one day?
Conservation and Prison Island entrance fees included since 11 February 2026. Free cancellation up to 24 hours.