To tell you the conclusion first to save you some time, travellers cannot fly drones in Korea.
Some of you might want to take videos using drone when you visit Korea. However, since Korea is divided nation, there are laws to protect the security of the nation. Regulations to drone filming is one of them. All people including Korean need to get permits to fly drones and to film using drones.
Let's see what you need. There are two things you need to consider:
Flight Permit
Film Permit
Before going into these detail, note that the drone weight should be less than 249g. If you are planning to use drone that weighs over 249g, then you need a license.
Flight Permit
When you download drone app and see the map of Korea, there are two parts. By the way, the app I am using is called Drone Fly.
App Store: https://apps.apple.com/kr/app/%EB%93%9C%EB%A1%A0%ED%94%8C%EB%9D%BC%EC%9D%B4-dronefly/id1193095248
Google Play: https://play.google.com/store/apps/details?id=com.jchyun.dronefly&pcampaignid=web_share
You can see that some parts are colored and some are not. For colored area, no matter what the color is, flight permit is required. For non-colored area, you do not need a flight permit.
To get a flight permit for the colored area, you need to request a permit through a website called Drone One Stop. This is where all the drone required stuffs are handled in Korea.
✔ Drone One Stop: https://drone.onestop.go.kr/
However, the website is all in Korean. So non-Korean speakers can't submit a form.
Film Permit
This permit is required for ALL drone use in Korea. Whether filming or not, if you are flying drone with camera, then you need a film permit. This permit can be obatain through the same website.
✔ Drone One Stop: https://drone.onestop.go.kr/
Conclusion
Unfortunately, it is not easy to fly a drone in Korea as a foreigner. First is because of the language barrier. The website does not offer English. Second is that there are many steps that are required to fly a drone, and foreigners cannot even start because the first step required a verification which asks for your Korea phone number. Therefore, travellers will face difficulties to fly drone in Korea.