Changuu Island lies about thirty minutes by boat from Stone Town, and almost everyone knows it as Prison Island. The name is a small historical joke. The island was bought by General Lloyd Mathews and a prison was built there in 1893, but no prisoner was ever held in it. Instead the buildings became a quarantine station during yellow fever outbreaks, and the ruins still stand today.
What draws visitors now is the tortoise sanctuary. A colony of Aldabra giant tortoises, originally a gift from the Seychelles, lives on the island under the care of a conservation team. The oldest animals are well over a century old. You are able to walk among them, feed them and photograph them at close range with a keeper present.
After the sanctuary and the prison ruins, the rest of the visit belongs to the water. The island is ringed by a shallow reef and a small white beach, so there is time to snorkel, swim or sit in the shade before the boat returns to Stone Town.
Prison Island runs as a half-day trip and pairs naturally with Stone Town, the spice farm or Nakupenda Sandbank for a full day.