Jeju Island is the largest island in South Korea, located in the Jeju Province. The island lies in the Korea Strait, below the Korean Peninsula, south of the South Jeolla Province.

Taiwan, officially the Republic of China (ROC), is a country in East Asia. Neighbouring countries include the People's Republic of China to the northwest, Japan to the northeast, and the Philippines to the south. The main island of Taiwan has an area of 35,808 square kilometres (13,826 sq mi), with mountain ranges dominating the eastern two-thirds and plains in the western third, where its highly urbanised population is concentrated.