Phú Quý - also known as Cù Lao Thu or Cù Lao Khoai Xứ - is a coral island 120km off the coast of Bình Thuận province in the East Sea, now administratively part of Lâm Đồng province. The island is approximately 16km² with a permanent population of around 30,000 people, predominantly engaged in offshore fishing. It sits on a raised coral platform that gives the surrounding water exceptional clarity - visibility of 15-20m is common in the dry season, making Phú Quý one of the better diving destinations in southern Vietnam.
Tourism infrastructure is modest: basic guesthouses, a handful of restaurants, motorbike rentals, and a small number of dive operators. There is no resort development and the island retains a genuinely working character - the kind that disappears quickly once resorts arrive.