As the number of tourists visiting Jeju Island and the migration population from other regions increases steadily, we may expect that a total of one million people will reside in Jeju with a net population of 800,000 and visitors of 200,000 in 2040. Jeju has been currently preparing policies for the era of a 1 million population, including the improvement of traffic and settlement conditions to prevent indiscreet unsustainable development and to minimize the side effects caused by the rapid population expansion. In the future, Jeju will have to establish a policy to create a sustainable Jeju in all fields such as economy, industry, welfare, environment, society, culture, etc. Therefore, we need to seek the potential direction of sustainable Jeju and feasible strategies to protect the livable Jeju in the future.