In 1893, Lloyd Mathews built the prison. The prison idea was to send violent criminals from the Tanganyika mainland to the Prison Island. The Prison Island ended up being used as a quarantine center, instead of a prison, for yellow fever epidemics that once raged through the region. Prison Island remained in the ownership of the government which converted the newer quarantine buildings into a guest house.
In another part you will get a time to see the giant tortoises which grow up to 200years old and they have a weight up to 200kg you can feed them and and taking a photo with them
*The price is per person and include entrance fee, and boat for those who stay in stone town if you stay out of stone town don't hastate to contact me for transport for good price.