Halong Bay Vietnam Halong bay (Vịnh Hạ Long in Vietnamese) is a UNESCO World Heritage Site, located in the Gulf of Tonkin, 170 kilometres east of Hanoi, Vietnam. The bay has a 120 kilometre long coastline and is approximately 1,500 square kilometres in size, includes some 1,600 islands and islets, forming a spectacular seascape of limestone pillars. Because of their precipitous nature, most of...