For comprehensive information about visa requirement, please refer to this website. (You can switch language to English or Chinese.)
For participants from Taiwan, Hong Kong, Japan, United States, Canada: You do NOT need a visa. You can visit Korea for up to 90 days (6 months for Canadian citizens) for short term visit purpose. (Tourist via B-2-1)
For participants from China mainland
You DO need a visa if you arrive at Seoul Incheon Airport and must transfer to Seoul Gimpo Airport. You will need to obtain in advance an Ordinary Tourist visa for South Korea to travel between Incheon and Gimpo.
You DO NOT need a visa if you fly to Jeju directly (without transferring through Seoul Incheon Airport). If you fly this way, you can visit Korea for up to 30 days. You can also visit Korea without a visa, if you are Frequent Visitors who have entered Korea at least 4 times within the past 2 years, or 10 times in your total travel history, and have never violated Korean laws or overstayed in Korea before.
For any visa or logistical questions please contact Jiwon Park at firstname.lastname@example.org