If you’re spending time in Zanzibar, someone will eventually mention Prison Island. It comes up in almost every itinerary. Boats leave regularly from Stone Town, the crossing takes about 20–30 minutes, and the island has become one of the most visited spots around Zanzibar.

Still, it’s worth going—if you know what you’re actually going for.

Prison Island isn’t really about prisons. And it isn’t just about giant tortoises either. It’s a mix of strange colonial history, surprisingly calm beaches, and one of the oldest tortoise populations in East Africa.

Most people rush through it in an hour. That’s usually where the trip falls a bit flat.

Stay longer and it starts to make more sense.

Getting to Prison Island

The island is officially called Changuu Island, though almost nobody uses that name anymore.

You’ll leave from the waterfront in Stone Town. Small wooden boats with outboard engines line the shore, and boat captains are easy to find near Forodhani Gardens.

The ride is short but pleasant. The water here is usually calm and shallow, shifting between pale blue and turquoise. If the tide is low, you’ll see sandbanks appearing around the boat.

One small tip that many travelers miss: go early in the morning if you can.

Late morning is when most tour groups arrive. The island isn’t huge, so crowds can make the tortoise area feel a bit cramped. The first boats of the day are quieter, and the light for photos is better.

The Giant Aldabra Tortoises

Let’s start with the main attraction.

Prison Island is home to a population of Aldabra giant tortoises, some of which are well over a century old. They were originally gifted to Zanzibar by the Seychelles in the late 1800s.

A few of the oldest ones are believed to be around 150 years old.

When you first walk into the tortoise sanctuary, the size of these animals is a little surprising. Some are massive. Thick legs, heavy shells, slow deliberate movements.

They don’t seem bothered by visitors, though they definitely know when food is coming.

Staff sell small bundles of greens you can feed them, and the tortoises will slowly wander toward you once they notice. One nudged my leg gently with its shell while reaching for leaves. Not aggressive—just determined.

Most people spend ten minutes here taking photos and move on.

But if you hang around a little longer, you’ll notice the smaller tortoises too. Some are juveniles only a few years old, kept in a separate enclosure for protection.

This breeding program is one reason the population here has stayed stable.

The Strange History of the “Prison”

Despite the name, Prison Island never really functioned as a prison in the way people imagine.

In the late 1800s, the British built a large stone building on the island that was intended to house rebellious slaves from mainland Zanzibar. But it was never actually used for that purpose.

Instead, the building became a quarantine station for people arriving in East Africa during outbreaks of disease, particularly yellow fever.

Ships entering Zanzibar would stop here, and passengers suspected of illness were isolated on the island before entering the city.

When you walk through the old building today, you can still see its long corridors and simple rooms. The architecture is solid but plain. Coral stone walls, wooden shutters, wide verandas facing the ocean.

Most visitors spend only a few minutes inside. Personally, I think it’s worth slowing down here.

The building tells a quiet story about colonial medicine and trade routes across the Indian Ocean. Zanzibar was a major hub in that network.

Swimming and Snorkeling Around the Island

Many people don’t realize Prison Island also has some nice swimming spots.

The water on the western side is clear and shallow, and there’s a small beach where visitors can relax. Some tours include snorkeling gear, though the coral here isn’t the best you’ll find around Zanzibar.

You’ll see fish and patches of reef, but it’s not spectacular.

Still, jumping into the water after walking around the island feels good—especially in the afternoon heat.

One thing to watch: the tide changes quickly.

At low tide, parts of the shoreline become rocky and harder to access. If swimming is part of your plan, ask your boat captain about the tide schedule before leaving Stone Town.

This is a small detail that trips sometimes overlook.

Walking Around the Island

Prison Island itself is small. You can walk around most of it in under an hour.

There’s a short path circling the island with views toward Zanzibar’s coastline and Stone Town in the distance. On clear days, the city’s skyline is visible across the water.

The pace here slows down once the day-trippers leave.

You’ll hear waves hitting the rocks and occasionally see peacocks wandering around the grounds near the old building. They were introduced years ago and somehow became part of the island’s character.

There’s also a small restaurant and bar near the main dock. The food is simple—grilled fish, rice, cold drinks—but the shaded terrace is a good place to sit for a while before heading back.

Combining Prison Island With Other Zanzibar Trips

Prison Island rarely takes a full day. Most visits last two to three hours.

That’s why it’s often combined with other activities around Zanzibar.

One popular option is pairing it with Stone Town walking tours in the morning. You explore the narrow streets, historic buildings, and markets first, then take a boat to the island later in the day.

Another common combination is adding it to Zanzibar island and spice tours.

Those tours usually include visits to spice farms outside Stone Town where you can see cloves, nutmeg, vanilla, and cinnamon growing. Guides show how spices shaped Zanzibar’s economy for centuries.

Adding Prison Island afterward creates a nice mix of nature, history, and local culture in a single day.

Just don’t try to pack too much into the schedule. Zanzibar moves best at a slower pace.

Small Things That Make the Visit Better

A few practical tips that help the experience.

Bring cash for entrance fees and boat rides. Some places accept cards, but it’s not guaranteed.

Wear light shoes or sandals. The paths are uneven in spots, especially near the shoreline.

And bring water. The island gets hot quickly, and shade is limited outside the main buildings.

One last thing: respect the tortoises.

They’re calm animals, but occasionally visitors try to climb on them for photos. It happens more often than you’d expect. Don’t do it. The staff discourage it, and it’s stressful for the animals.

Final Thoughts

Prison Island isn’t the most dramatic place in Zanzibar. It’s small, a little touristy at times, and easy to rush through.

But if you slow down, it becomes surprisingly enjoyable.

The giant tortoises alone make the trip memorable, especially when you realize some of them were already alive long before modern tourism reached Zanzibar. The old quarantine building adds a layer of history that connects the island to the wider story of trade and travel across the Indian Ocean.

And the boat ride from Stone Town—short as it is—offers a different perspective of the coastline.

If you’re planning your trip, consider adding Prison Island to a broader itinerary that includes Zanzibar island and spice tours, a walk through Stone Town, and some time on the quieter beaches around the island.

Give yourself a few relaxed hours here rather than a rushed stop.

Feed the tortoises. Walk around the shoreline. Sit by the water for a bit before heading back.

Sometimes the smaller places end up being the most memorable ones.