There are more than 25 beaches on this island.
The best beaches are situated in the North and the East of the island (Bweju, Jambiani, Page). All the beaches are worth a visit though. The shores are protected by a reef that surrounds the whole of Zanzibar.
The whole island is affected by the tides (about 3 meters).
At low tide the beach can be very different and you could end up walking up to 2 km in order to reach the water.