Before you go
You must have a passport valid for six months after the date of your departure from Zanzibar as well as a Tanzanian visa. No visa, no entry to Zanzibar. You can buy a visa on arrival although it can be a pretty stressful way of entering the country. It’s much better to buy one before you leave the UK.
You don’t need any injections to visit the islands, although Yellow Fever is recommended and will be essential if you combine your trip with other African destinations (apart from Kenya and Uganda). You must take a course of anti-malaria tablets which you should start before you leave the UK. Malarone is one which has few side-effects.

While you’re there
Zanzibar is poor with most of its 1 million inhabitants existing on little more than a dollar a day. Expect to see poverty, shanty towns and sad hovels along the roadsides. This may shock you but what the Zanzibaris lack in material possessions they make up for in spirit and generosity.
Please bear in mind that almost all Zanzibaris are Muslim and show due respect by covering shoulders and legs when not on the beaches or in resorts.