Dadan Island (Tatan, Taitan Island, Tae-tan/Taetan) (, originally ) is an island in Lieyu Township, Kinmen County, Fuchien Province, Republic of China (Taiwan). The island is in the Taiwan Strait, along the coast of Mainland China. It is located approximately to the southwest of Lesser Kinmen (Lieyu) and approximately from Xiamen (Amoy).
In March 1853, HMS Rattler struck a sunken rock at Amoy, China and was severely damaged. She was beached at Tae-tan (Dadan) for repairs.
Since 1949, Dadan Island has several times become the battlefront of conflicts between the People's Liberation Army and the Republic of China Armed Forces.
On July 26, 1950, ROC forces on the island, in total 298 soldiers, repulsed an attack () from a People's Liberation Army force of 700 soldiers that landed on the island.
In October 1951, Chiang Ching-kuo visited the island and gave the island its current name.
Chinese Nationalist spokesmen reported that Chinese Communists shelled Dadan and Erdan between June 26âÂÂ28, 1957. At that time, Chinese Nationalist strength on the islands was around 1,100 men.
On May 9âÂÂ10, 2002, President Chen Shui-bian visited Dadan (Tatan) and delivered remarks concerning Cross-Strait relations.
On 30 June 2014, the control of the island and surrounding islets was handed over from the Republic of China Armed Forces to the civilian under the Coast Guard Administration of Kinmen County Government.
From 26 July until 31 October 2018, the island was opened to the public on trial basis which attracted 3,000 people in total. On 1 March 2019, the island was officially opened for tourism. A maximum of 150 people can visit the island on a given day and sight-seers must apply for permission to visit ten days before their visit. Residents of mainland China, Hong Kong and Macau are prohibited from visiting the island.
In July 2024 the Kinmen County Government said tours to the island would resume on a trial basis.
The total surface area of Dadan Island is . The northern and southern part of the island are more elevated than its central area, which contains a strip of sandy beach. Mountains on the island include Beishan ('north mountain', Mt. Beishan; ) which reaches above sea level, Mt. Xiaohu ('little tiger mountain', Mt. Siaohu; ) which reaches above sea level, and Nanshan ('south mountain', Mt. Nanshan; ) which reaches above sea level.
Erdan Island is from Dadan Island at the closest point.
Dadan Island is the largest of a small group of islets which also includes Erdan Island, Sandan Island (), Sidan Island (), Wudan Island (), Menghu Islet, etc. They sit astride the entrance into the Xiamen (Amoy) Harbor from the Taiwan Strait.
The islands of Wu Yu and Qing Yu in Gangwei, Longhai City, Zhangzhou, Fujian, China are located to the south of Dadan Island.