The Oki Islands UNESCO Global Geopark encompasses the Oki Islands, which are located in the western Sea of Japan and their surrounding sea area. The four inhabited islands include Dōgo Island, and the three Dōzen Islands: Nishinoshima, Nakanoshima and Chiburijima.

Here you see rocks created by former volcanic activity and characteristic coastal landscapes shaped by wave erosion. The three Dōzen Islands are the remains of a caldera that was created by volcanic activity six million years ago.

The sea between the Oki Islands and mainland Honshū Island has a depth of less than 100 metres. As a result, the islands became connected to the mainland during the ice ages that occurred during the Quaternary Period. A unique ecosystem has formed here influenced by these climatic changes and the currents of the Sea of Japan.