Giant Aldabra Tortoises
Meet — and gently feed — a colony of century-old Aldabra giant tortoises in their protected sanctuary.
Zanzibar
Zanzibar Archipelago
Prison Island
Home to giant Aldabra tortoises, historic buildings, excellent snorkelling, and beautiful beaches just off Stone Town.
In pictures
Prison Island through the lens
Overview
Also known as Changuu Island, Prison Island sits a short boat ride off Stone Town. Never actually used as a prison, it is now home to a colony of giant Aldabra tortoises — some over a century old — plus a small beach, snorkelling reef and atmospheric colonial ruins.
Highlights
What to see & do
- Giant Aldabra tortoises
- Historic colonial buildings
- Excellent snorkelling
- Beautiful beaches near Stone Town
Best time to visit
When to go
Jun – Oct & Dec – Feb
Year-round; mornings are calmer and cooler for the tortoise sanctuary
Combine with a Stone Town walking tour for a relaxed half-day.
How to get there
Getting to Prison Island
- 01
30-minute traditional dhow or motorboat ride from Stone Town seafront.
- 02
Boats depart daily from Forodhani Gardens jetty.
- 03
Half-day tours can be arranged through your lodge or on the seafront.
Located just a short boat ride from Stone Town, Prison Island — also known as Changuu Island — is one of Zanzibar's most popular excursions. Although it was originally intended to serve as a prison and later used as a quarantine station, today the island is best known for its giant Aldabra tortoises, crystal-clear waters, white-sand beaches, and fascinating history.
Prison Island combines history, wildlife, and coastal beauty in a single destination. Visitors can meet century-old giant tortoises, explore historic buildings, snorkel vibrant coral reefs, relax on peaceful beaches, and enjoy panoramic views of the Zanzibar coastline.
Why visit
Why Visit Prison Island?
Prison Island is Zanzibar's easiest and most rewarding half-day trip — a short dhow ride from Stone Town delivers giant tortoises, colonial ruins, snorkelling and a swimmable beach.
Chapter one
History of Prison Island
Prison Island lies approximately 5.5 kilometres northwest of Stone Town and is reached by a scenic 20–30 minute boat ride. Purchased in the 1860s by an Arab trader and later acquired by the British in 1893, the island was built as a prison for rebellious slaves but never actually held any prisoners.
It was subsequently used as a quarantine station for yellow fever cases arriving from the mainland. The famous Aldabra giant tortoises were gifted to the island in 1919 by the governor of the Seychelles — their descendants still live here today, some over a century old.
Not to miss
Top Attractions in Prison Island
Historic Prison & Quarantine Buildings
Tour the original coral-stone prison and quarantine ruins, complete with cells and interpretation boards.
Snorkelling
Clear water and coral gardens just offshore, with tropical fish, sea stars and octopus.
The Beach
A small, sheltered white-sand beach ideal for swimming and picnicking.
Peacocks & Birdlife
Resident peacocks and a range of coastal bird species roam the island freely.
Scenic Boat Ride
The dhow crossing itself is a highlight — panoramic views back over Stone Town's skyline.
Living heritage
Cultural Experiences
Prison Island is a compact window on Zanzibar's colonial and Indian-Ocean history — from slavery and quarantine to conservation and wildlife tourism today.
Shopping
Take a piece of Zanzibar home
- Small kiosk on the island with cold drinks and light souvenirs
- Full craft, spice and antique shopping back in Stone Town
Must-try dishes
Best restaurants & street food
- Light snacks and drinks at the island café
- Most visitors return to Stone Town or Forodhani for lunch
- Full-day tours can be combined with a beach picnic at Nakupenda Sandbank
Where to stay
Accommodation for every style
Day Trip Only
- Prison Island has no overnight accommodation for general visitors
- Stay in Stone Town and visit as a half-day excursion
When to go
Best time to visit
June – October
Cool, dry and calm — the best window for the boat crossing and snorkelling.
December – February
Hot and clear with excellent underwater visibility.
March – May
Long rains — trips still run but conditions can be choppy.
Morning Departures
Cooler for tortoise viewing and calmer sea conditions.
Plan your visit
Suggested itineraries
Half-Day Excursion
- 109:00 depart Stone Town by dhow
- 2Tortoise sanctuary and prison ruins
- 3Snorkel and swim from the beach
- 413:00 return to Stone Town for lunch
Full-Day Combo
- 1Prison Island in the morning
- 2Nakupenda Sandbank for lunch
- 3Sunset dhow cruise back to Stone Town
Safari + beach
Combine Prison Island with a Zanzibar beach escape
Prison Island pairs naturally with Stone Town sightseeing and nearby island excursions.
Why Williamson
Why book with Williamson Adventures?
Williamson Adventures offers professionally guided Prison Island excursions with private boat transfers, knowledgeable local guides, customizable itineraries, and seamless combinations with Stone Town tours, Zanzibar beach holidays, and Tanzania safaris.
Good to know
Frequently asked questions
No — it was built as a prison in the 1890s but never used as one. It later served as a yellow-fever quarantine station.
The oldest residents are over 100 years old, descended from a group gifted from the Seychelles in 1919.
Typically 2-4 hours, including the boat rides, tortoise sanctuary, prison tour and a snorkel or swim.
Comfortable walking shoes, swimwear, reef-safe sunscreen, drinking water, a hat and a camera.
Keep exploring
Other Zanzibar destinations
Stone Town
A UNESCO World Heritage Site, Stone Town is the cultural and historical heart of Zanzibar, blending African, Arab, Persian, Indian, and European influences.
Nungwi
Zanzibar's premier beach destination, known for white-sand beaches, turquoise waters, luxury resorts, and year-round swimming.
Kendwa
Kendwa Beach is celebrated for calm waters, spectacular sunsets, soft sand, and a relaxed yet lively coastal atmosphere.