Situated about from Vũng Tàu and from Saigon, the group includes 16 mountainous islands and islets. The total land area reaches and the local population is about 5,000. The islands are composed ofmagmatic rocks of different ages. Hòn Bảy Cạnh, Hòn Cau and Hòn Bông Lang are composed of cretaceous microgranit rocks. The northern part of Côn Đảo Island is composed of quartz diorite and granite - granodiorite of late mesozoic- early cenozoic age, and is partially covered by quaternary marine sediments. The southern part of this island and Hòn Bà island are composed of the rhyolite and intrusive formations of unknown age. On the western slope of Côn Đảo Island, there exist groups of outcrops of diorite and microgranite penetrated by big quartz bands . The island group is served by Côn Đảo Airport situated on the largest island in the archipelago, Côn Sơn Island.
History
Formerly a Khmer Empire territory known as Koh Tralach, កោះត្រឡាច , the islands were settled by the Vietnamese by the 17th century. On June 16, 1702, the English East India Company founded a settlement on Pulo Condore as an entrepôt for ships plying between India and China. Three years later, on 2 March 1705, the Vietnamese murdered the English agents, destroyed the factory, and expelled the remaining settlers. During the internecine wars for the Court of Huế, the Nguyen Prince Nguyễn Phúc Ánh ceded the islands to France in the Treaty of Versaillesin return for military assistance. The treaty however was abrogated as France failed to provide the aid. It was only under conquest that the islands came under French control in 1861. During the French colonial era Côn Sơn Island was made infamous for its penal facilities and the notorious "tiger cages". Vietnamese and Cambodian nationalists and revolutionaries were sent here to serve their sentence for anti-French activities. Many Vietnamese Communist leaders were "schooled" on Côn Đảo Island as well. The French Indochinese government named the group of islandsPoulo-Condore Islands, a name that derives from the islands' Malay name Pulo Condore.
Many of the islands were given protected status in 1984 as part of Côn Đảo National Park. This natural preserve was subsequently enlarged in 1998. Endangered species protected within the park include the hawksbill turtle, the green turtle, dolphins, and the dugong. Ecosystems represented in the park include seagrass meadow, mangrove and coral reefs. Côn Đảo National Park is working with the World Wildlife Fund Vietnam to further protection in the marine areas, with programs to establish a Marine Protected Area that protects coral reefs, seagrass beds and species, while also developing sustainable nature-based ecotourism. The island's management is strongly geared towards sustainable use, hoping to learn from previous experiences in Vietnam and the region to balance development with conservation.
Ferry
A new hydrofoil service from Vũng Tàu to Côn Đảo was started in February 2019. The service is a daily return and boasts that the ferry will operate year round, regardless of the weather. Travel time is 4–5 hours, departing Vũng Tàu at 8am and returning from Côn Đảo at around 2pm. Two ferries operate between Côn Đảo and the mainland. There is a daily overnight hour ferry service from Vũng Tàu which, in addition to bringing passengers, serves as the main source of importing goods to the islands. The ferry operates on a daily basis, however in winter months the service depends largely on weather conditions as the seas between Côn Đảo and the mainland can be rough. In 2016 a new ferry service primarily for passengers opened up between Sóc Trăng and Côn Đảo, shortening the length of the journey to three hours. With the addition of a fast ferry to the islands, the islands have experienced an increase in tourism fueled mostly by domestic tourists who view Côn Đảo as a sacred place due to its history.
