A cluster of around a dozen small islands off the southern tip of Phu Quoc, the best snorkelling and diving territory around the island. The coral reefs here are in better condition than the mainland Vietnamese coast, with reasonable visibility and a reasonable variety of reef fish, sea turtles, and — with luck — leopard sharks in the sandy channels between islands.
Day trips by boat from An Thoi port run several times daily, typically including three or four island stops, snorkelling, and lunch. The trip takes around 4–5 hours. Diving operators in Duong Dong and at the main resort hotels offer full-day scuba excursions to the archipelago. The best diving season is November to May.