Hallyeohaesang National Marine Park was designated as the first national marine park in 1968 and covers the area between Jisimdo Island in Geoje and Odongdo Island in Yeosu with six separate districts including Geoje, Tongyeong, Sacheon, Hadong, Namhae and Odongdo Island. It spans over an area of 535.676 ㎢ and the ocean accounts for 76% of the total area. The outstanding view created by the sea and land attracts over 1 million visitors every year.

The Tongyeong district of the park encompasses Dadohae Islets, Bijindo Island and Haegeumgang Islets. The Donam Complex in Tongyeong is being developed as a world-class marine tourist attraction. On Hansando Island, there are many historical sites dedicated or related to the great Admiral Yi Sun-sin, such as battlefields where the admiral defeated Japanese naval forces. Other sites include those related to the Imjin War such as Jeseungdang, Chungnyeolsa and the turtle lighthouse. The Sanyang Road is a great driving course along where one can see the entire Mireukdo Island and appreciate the scenery. From Dara Park, visitors can enjoy the great view of Dadohae Islets. Major attractions include Hansando Island, Bijindo Island and Maemuldo Islands; the latter two are often said to be the focal point of this scenic sea park.