Phu Quoc is closer to Cambodia than to Saigon, and it has spent its history making two things: pepper and fish sauce. Both are still made the way they were, in gardens and in barrel houses you can walk into, and that is the island underneath the resorts.
Day one runs the north — a sim wine still, the pepper rows, Dinh Cau on its rocks at sunset, and Grand World after dark. Day two is the south: the pearl farm, the fish sauce barrels, the prison, then a boat out for fishing and snorkelling, and Sunset Town for the last of the light. Day three is breakfast and the airport.