Despite the disconcerting name, Mafia Island is a real paradise. Gold-flecked beaches that glow brilliant white under the endless African sun meet waters of azure blue and emerald green here. There are crooked Tanzanian coast cottages butting up against paint-peeling ocean canoes. There are charming locals, aged lighthouses, and – the main star – great swathes of protected marine habitat.

Mafia Island tour guides can help you organize your scuba dives or snorkeling expeditions out into the Indian Ocean. Whether you go for a full-on PADI course or just a casual snorkel, you're sure to see resplendent reefs where whale sharks, rare sea turtles, and big groupers all roam. If you're not one for getting wet, there are miles of pristine beachfronts waiting for lazing. You could go for the sand stretches running out from Ras Mbisi, fringed by age-old coconut groves or hit Bwejuu Island, where the palms stoop low over the lagoons.

There's history to see in these parts, too. Venture to the dig site at Ras Kisimani to find the ruins of a 12^th-century fishing town, now half claimed by the water. In Ras Mkumbi, meanwhile, there's are weathered lighthouse poking out from wild forests filled with monkeys.