Jozani-Chwaka Bay is Zanzibar's only national park and its one remaining significant forest. The heart of the park is a patch of mixed groundwater forest covering the central depression of the island, where high water tables and rich soil have allowed trees to grow to genuine height. The forest is home to around 2,000 Zanzibar red colobus monkeys — endemic to the island and listed as endangered — who have become so accustomed to visitors that family troops pass within metres on the forest trail.
The red colobus is one of Africa's rarer primates, recognisable by its russet-red back, white underparts, and long tail. It lives in large groups and moves through the canopy in a relaxed, unhurried manner, occasionally descending to the ground. The park authorities have controlled the guiding so well that the monkeys neither flee from visitors nor approach them for food; it is one of the more genuinely naturalistic wildlife encounters in East Africa.
Beyond the monkeys, the forest harbours Aders' duiker (another Zanzibar endemic), various small mammals, and a good range of birds including the endemic Zanzibar white-eye. The trail also passes through a section of mangrove on the edge of Chwaka Bay, with a boardwalk over the tidal mudflats. Allow 2–3 hours for a proper walk. Entry fees go directly to conservation; guided tours are compulsory and the guides are knowledgeable.
The park is about 35 km from Stone Town — roughly an hour's drive on roads that are mostly paved. It combines easily with a visit to a spice farm or the east coast beaches.