Yes. To visit Zanzibar you need a visa, but you don’t have to arrange this beforehand! It’s easy to collect the visa upon your arrival on the airpot of Zanzibar or Dar es Salaam. The costs of the visa are $50,-.
It works as follows, upon arrival on the airport you fill out a form with your details and where you are staying. Have you booked your accommodation yet on the kitespot at the Kahawa Suites? After this you go to the office where you pay the fee of $50,- (paying with creditcard is possible). After one final passport check and stamp you are welcome in Zanzibar! Karibu Sana!