Prison Island Zanzibar

Prison Island Zanzibar, also known as Changuu Island, is a small coral island sitting 5.6 kilometres northwest of Stone Town that offers visitors a guided walk through colonial-era ruins, close encounters with Aldabra giant tortoises, a small beach for swimming, and optional snorkelling in the surrounding Indian Ocean waters. The tour takes approximately three hours to complete the round trip. The island is around 25 to 30 minutes by boat from Stone Town. The island carries a layered history as a slave detention site, a prison that was never used as one, and a quarantine station, making it one of the more educational half-day excursions available from Stone Town in 2026.

A Quick Look at What to Expect on Prison Island

The History Behind the Name

The story of Prison Island is more complex than its name suggests. The island was uninhabited until the 1860s, when the first Sultan of Zanzibar, Majid bin Said, gave it to two Arabs who used it as a prison for rebellious slaves prior to shipping them abroad or selling them at the slave market in Zanzibar’s Stone Town.

The British First Minister of Zanzibar, Lloyd Mathews, purchased the island in 1893 and constructed a prison complex there, but no prisoners were ever housed on the island, and instead it became a quarantine station for yellow fever cases. The cells you see today were actually hospital rooms for patients waiting to be cleared for entry into Stone Town.

The old prison was converted into the facility’s hospital, and in 1923 the island was officially renamed Quarantine Island. Quarantine cases would be taken from ships and monitored on the island for between one and two weeks before being allowed to progress with their journey, with the main disease monitored being yellow fever. The name “Prison Island” stuck in popular use despite this later function, and it remains the name most travellers know today.

The Giant Aldabra Tortoises of Prison Island

The tortoises are the primary reason most visitors make the trip. In 1919 the British governor of Seychelles sent a gift of four Aldabra giant tortoises to Changuu from the island of Aldabra. These tortoises bred quickly and by 1955 they numbered around 200 animals, but people began to steal them for sale abroad as pets or for food, and their numbers dropped rapidly to around 100 in 1988, fifty in 1990, and just seven by 1996.

The Zanzibar government, with assistance from the World Society for the Protection of Animals, built a large compound for the protection of the animals, and by 2000 numbers had recovered to 17 adults, 50 juveniles, and 90 hatchlings. The species is now considered vulnerable and has been placed on the IUCN Red List by the International Union for Conservation of Nature.

The tortoises can reach roughly 122 cm in length with an average weight of 250 kg, and they are known to be among the longest-lived animals in the world, with the oldest tortoise on Prison Island estimated to be 196 years old. Visitors are allowed to feed them fresh spinach leaves provided by the keepers, though you should watch your fingers as they have a strong beak. You can also visit the nursery to see baby tortoises of various ages.

It is worth noting that some recent visitor reviews have raised concerns about the condition of the tortoise enclosures, particularly for younger animals. Go in with realistic expectations: the adult tortoises roam relatively freely, but the facilities are basic by international zoo standards.

What Else to Do on Prison Island

The old prison remains standing, providing shelter for some of the tortoises, and the cells can be visited. Walking the ruins with a knowledgeable local guide adds context that the site alone cannot convey, connecting the physical remains to the wider history of East African colonial trade routes and the slave economy centred on Stone Town.

The waters surrounding Prison Island offer snorkelling opportunities that are more suited to beginners or those seeking a gentle introduction to Zanzibar’s underwater world, with coral reefs sitting close to the surface in clear water. While Prison Island’s reefs may not match the spectacular diversity of Mnemba Island or the Menai Bay Conservation Area, they still harbour colourful tropical fish and provide good visibility for underwater exploration.

There is a small sandy beach on the island where you can swim, though the coral reef has seen better days due to high boat traffic. The beach suits a short cool-down after walking the ruins rather than a full beach day. Look carefully and you may also spot butterflies, bats, and the very shy duiker on the island. There are also peacocks and certain bird species found around the island.

How to Get to Prison Island from Stone Town

There is no public ferry to Prison Island, so you must hire a private wooden dhow, which is part of the experience. Walk to the beachfront near Forodhani Gardens or the Tembo House Hotel and you will see boat captains waiting with their boats. This is the most direct and affordable route.

The standard rate for a private boat covering the return trip is $20 to $30 USD total, not per person, depending on your negotiation. Organised tour packages from operators in Stone Town bundle the boat, guide, and entrance fee together. A standard tour costs approximately $40 USD per person with boat transfer, guide, and entrance fee included. A VIP private tour runs around $70 USD per person and includes private boat services and additional facilities. If you are travelling as a couple or solo, booking independently at the waterfront and paying the entrance fee separately tends to be cheaper.

Boats depart from Stone Town Beach near Forodhani Gardens, with the morning tour running from 9:00 a.m. to approximately 12:30 p.m. Morning visits are advisable to benefit from cooler weather and to avoid the peak crowds that arrive mid-morning on busier days.

Best Time to Visit Prison Island Zanzibar

The optimal time to visit is during Zanzibar’s dry seasons: June to October offers pleasant temperatures around 25 to 28°C with low humidity and calm seas, while December to February provides hot, sunny weather with excellent snorkelling visibility. The long rains from March to May can make the short boat crossing uncomfortable and visibility in the water drops noticeably. The island itself is accessible year-round, but sea conditions are the main variable to check before setting out.

Prison Island Zanzibar: Costs and Budget Breakdown

Practical Tips for Visiting Prison Island in 2026

The island is government-owned, and a US$12 entry fee is charged at the gate. Fees have fluctuated in recent years and some recent visitor reports cite figures of up to $22 per person, so carry more cash than you think you need. US dollars are widely accepted, but smaller notes are useful for the boat captain and any tips.

Arrive at the Stone Town waterfront early. The first boats typically leave around 9:00 a.m. and the island gets busiest between 10:00 a.m. and noon. Going early means smaller crowds around the tortoises and a cooler walk through the ruins. The boat ride is fully open to the sun, so bring sunscreen and a hat. Bring swimwear if you plan to enter the water, and carry your own water bottle since the small restaurant on the island may not always have cold drinks available.

Dress modestly for the boat landing, as you pass through a local working environment before reaching the island. Wear normal clothes and water shoes for walking, and bring swimming clothes if you plan to swim, but avoid wearing very short clothing as you will encounter local residents and staff.

You can book a boat directly at the Stone Town waterfront or arrange transport through local tour operators. If you book through an operator, confirm exactly what is included in the price before agreeing, specifically whether the entrance fee, guide, and snorkel gear are all covered.

Combining Prison Island with Other Zanzibar Excursions

Combo tours involving Prison Island bundled with other sites, such as Nakupenda Beach, are available at varying prices from most Stone Town operators. Nakupenda is a sandbar that appears at low tide and is usually combined as a morning stop before or after Prison Island on the same boat journey. This makes for a full half-day on the water without extending costs significantly.

For those spending several days in Stone Town, Prison Island pairs well with a Stone Town walking tour through the historic alleys, a visit to the old slave market memorial, and a spice tour in the interior. Combining the Prison Island visit with Stone Town’s slave market memorial gives a more complete understanding