Prison Island, also known as Changuu Island, is located off the western coast of Zanzibar, just a short 30-minute boat ride from Stone Town. The island is surrounded by three smaller islands: Grave Island, Snake Island, and Bawe Island. Its main attraction is the famous giant tortoises, some of which can live for over 200 years.

Originally, the island was used as a detention site for rebellious slaves by the sultans from the 1860s until the end of the slave trade. Later, under the supervision of British First Minister Lloyd Mathews, a prison was built on the island in 1894. Despite its name, the facility was never used as a traditional prison; instead, it functioned as a quarantine station for potential yellow fever cases.

Today, Prison Island is a popular tourist destination, especially for its giant tortoise sanctuary. These Aldabra tortoises, imported from the Seychelles in the 19th century, are friendly and approachable. Visitors have the unique opportunity to feed and even pet these gentle giants, some of which are over a 100 years old. Beyond the tortoises, the island offers beautiful views and a tranquil escape just minutes away from the bustling streets of Stone Town.