Go Collecting Chogae (Clams) along the Shore.
Jeju Is famous for Seafood. Seafood is almost synonymous with seafood. Its even possible to eat whale here. Yes, :o/ !
Anyway fresh Sushi (Hwae) is wonderful here, and surprsingly cheap. Also Jeju Island Haemeul Tang (seafood soup) is well known throughout the country.
At low tide all over Jeju, you will see women and children collecting Chogae (shellfish) which they will use to make Haemeul Tang. Its a well loved food and fun to collect shellfish for.