Travel Guide to Prison Island, Tanzania: Things to Do & History

Discover Changuu Prison Island, with pristine white-sand beaches and over a hundred Aldabra tortoises. The island was once connected with Stone Town's disturbing slave trade history. Over time, it transformed from a never-used prison to a quarantine station and eventually a sanctuary for a unique and vulnerable species.

Short History

Changuu Island, also known as Prison Island, is a two-hour boat trip from Dar es Salaam and a 30-minute boat ride from Stone Town in Zanzibar. Despite only being around half a mile (0,8 km) long and 750 feet (229 m) wide, the island has a broad and varied history. 

The island is believed to have originally been uninhabited. In the mid-1860s, it was sold to Arab slave traders by Majid bin Salid, Zanzibar's first Sultan. The island's purpose was to be a place to punish and subdue enslaved people who were deemed difficult or trying to run away from where they were held in Stone Town, a major slave trading port until 1873.

In 1891, the British formed a constitutional government in Zanzibar, and Lloyd Mathews was appointed as First Governor. One of Mathews' projects was to turn the island into a prison. The project was completed in 1894, earning the area the nickname Prison Island. 

By that point, yellow fever was a problem in some port cities of West Africa and Europe. There had also been a cholera outbreak in Egypt, and India had been dealing with the bubonic plague. It was decided a quarantine station was needed between Zanzibar and Tanzania. Thus, the island found a new purpose. 

However, Changuu Prison Island was only needed for quarantine purposes during the shipping season. The rest of the year, locals used it as a resort for vacations and parties. 

In 1919, the island received its first permanent residents: four giant Aldabra tortoises. These animals lived on the island, growing their numbers as quarantine residents and holidaymakers came and went. 

In 1931, a new quarantine facility became available, and the island's days of dealing with the potentially ill were over. 

As the tortoises continued to live on, the buildings around them began to collapse. It wasn't until 2002 that the island began to rebuild the historic buildings to serve visitors who come to meet the tortoises that now number over 100.

Things To Do

Chenguu Prison Island may not be large, but it is still a pleasant way to spend part of your day. Whether you are in the mood to chill on the beach or meet a tortoise or hundred, there is always something to do. 

Learn History in Stone Town

Visitors should spend time in Stone Town learning its history before venturing to Prison Island, as the two are intertwined. The Portuguese fort dates back to the 18th and 19th centuries and has roots in many cultures, including:

• Arabic

• European

• Indian

• Persian

However, behind this rich blend of cultures and architecture is a disturbing period of slave trading between 1830 and 1873. It is estimated that 600,000 enslaved people passed through the port before the British abolished slave trading in Zanzibar. 

Fascinatingly, the early pre-Portuguese history of Stone Town is currently being rewritten. In 2017, a team of archeologists headed by Mark Horton and Tim Power began finding evidence of stone buildings and international trading well before the fort was established. 

The project now collaborates with the Zanzibar government, the University of Zanzibar, three international universities, and archeologists from Abu Dhabi's Department of Culture and Tourism. 

When visitors are full of history, they should also take the opportunity to appreciate the richness of Stone Town. It is bursting with delicious food, an incredible music scene, and more.

Admire the Aldabra Tortoises

Changuu Prison Island has transformed from a place of pain and despair to a sanctuary for Aldabra tortoises. Oddly, the tortoises are not native to the island. 

In 1919, the British governor of the Seychelles decided to send four giant reptiles to Chenguu as a gift. It was a heavy present, given the average Aldabra tortoise on the island weighs 550 pounds (250 kg).

Life on Changuu for the tortoises has been far from drama-free. Initially, they flourished, numbering over 200 by mid-1950. However, their popularity nearly destroyed them. Demand rose, with people wanting them as exotic pets or cuisine. The poaching became so dire that by 1996, Changuu's population had been reduced to seven. 

By 2016, the conservation group had managed to get the tortoise numbers to over 100. They now wear numbers on their shells to help keep track of them. The tortoises enjoy a good neck scratch, but signs on the island plead with people not to sit on them or feed them.

Aldabra tortoises are on the Red List of the International Union for Conservation of Nature as "vulnerable." Aldabra Atoll is the only place they live in the wild; in 2022, their population was 30. Conservation projects, like the one on Changuu, are essential for the continued survival of the Aldabra tortoises.

Tour the Slave Quarters

The prison and slave quarters of Chenguu Island have been converted into a museum. The director explained the museum's purpose is as an "education resource, offering visitors a comprehensive understanding of the island's historical context." There is information on the history of the island and Zanzibar. The museum also includes a bookstore and a small gift shop. 

Relax on the Beaches

Relax on Chenguu Prison Island's white-sand beaches. It's the perfect place to read a book, nap, snap photographs, and let all your stress and worries float away.

Swim in the Crystal-Clear Waters

Pack your swimsuit, as the crystal-clear waters off Chenguu Prison Island are a treat. However, please ensure your sun protection is ocean-safe (reef-safe) due to the nearby coral and marine wildlife. There are chemicals in some sunscreens and gels that can harm the fragile aquatic ecosystem. 

Snorkel Around the Coral Reef

Chenguu Prison Island is near a coral reef that attracts marine life, making it an enjoyable spot for snorkelers. Visitors are welcome to pack their gear, although many boats that ferry visitors have snorkeling gear available. 

Interesting Facts

Here are 10 interesting facts about Aldabra tortoises and Changuu Prison Island:

1. Some of the island's Aldabra tortoises are over 150 years old. 

2. The prison that gave the island its nickname never held a single prisoner.

3. Aldabra tortoises lay 9-25 eggs, but only 3-5 produce viable young.

4.  Other wildlife on the island includes peacocks, suni, duikers, bats, frogs, lizards, and Sykes monkeys. 

5. Aldabra tortoises are not natural to Prison Island. Seychelles is their native home.

6. Male Aldabra tortoises "court the ladies" by battering his shell against a female at least a dozen times.

7. It isn't clear how long an Aldabra tortoise can live. Jonathan in St. Helena is officially the oldest and was declared at least 192 in December 2024, although he may be even older. 

8. The island has used armed guards at night to prevent poaching and kept the hatchling cage secret. 

9. Aldabra tortoises love their vegetables, but they are not vegetarians. They've even been caught snacking on their dead brethren.

10. Aldabra tortoises' heart beats once every 10 seconds, or six beats per minute, while resting. 

Best Time to Visit

Changuu Prison Island is enjoyable to visit throughout the year. However, like visiting the rest of Zanzibar, the best months to visit are in the dry season. Outdoor activities are more enjoyable when the weather is nice. 

The dry season is also ideal if you plan to enjoy some Tanzania Safaris as part of your visit to the country. See our chart for more information to help you decide when to explore Prison Island and beyond. 

How Many Days Do I Need in Prison Island?

Visitors need at least three hours to visit Chenguu Prison Island, making it the perfect half-day outing. In addition to the tortoises, there is snorkeling and the beach to explore. 

What Islands Are Near Prison Island?

Chenguu Prison Island isn't the only island near Stone Town. Some are privately owned. However, there are two nearby that, despite their protected status, allow visitors to come and enjoy their natural splendor. 

Chumbe Island

Chumbe Island is a historic marine park and forest reserve. It's a quick boat trip from Stone Town. But bookings are essential, as visitor numbers are limited to protect the fragile ecosystem. 

Chumbe Island visitors can participate in:

• Guided forest walks.

• Snorkeling or scuba diving expeditions led by a marine expert.

Bawe Island

Bawe Island is a 30-minute ferry ride from Zanzibar. The peaceful area has conservation status, and visitors are asked to be mindful of the fragile ecosystem and follow the rules and regulations. Visitors come to snorkel, scuba dive, fish, and swim. 

An array of colorful fish hang out in the surrounding coral reef. Other marine life highlights include:

• Dolphins

• Sea turtles

• Whale sharks

Are Whale Sharks Dangerous?

Whale Sharks are often spotted by visitors to Chenguu Prison Island and other parts of Zanzibar who participate in water activities like snorkeling and scuba diving. Despite being the largest shark species, they are docile and fill their bellies on plankton. The massive creatures move slowly and are a joy to observe. Many who encounter them feel they are the highlight of their dive or snorkel. 

Can I Go on Safari After Visiting Zanzibar?

Many visitors enjoy vacationing in Zanzibar before or after their Tanzania Safari adventures. There are fantastic tours that visit various places, including:

• Serengeti National Park

• Ngorongoro Conservation Area

• Lake Manyara National Park

• Tarangire National Park

Does Tanzania Have Yellow Fever?

There has never been a reported case of yellow fever in Tanzania and Zanzibar despite the history of Chenguu Prison Island. The quarantine precautions back then were to prevent the disease from being brought into the region by ships rather than fears of the disease coming out.

Tanzania does not require travelers to be vaccinated against yellow fever unless they originate from a country at risk of the disease. Thus, travelers from Europe, North America, Southern Africa, and many other parts of the world do not need to worry about the requirement. 

Conclusion

Adventure seekers love traveling, but it has its stresses and frustrations. Changuu Prison Island is a fantastic opportunity to unwind on the beach, relax with tortoises, and be in the moment while snorkeling. The island is an excellent way to rejuvenate before heading towards your next exciting journey. So, check out our Tanzania Safaris tours and pack your bags for unforgettable African memories.