Jeju has a couple large tea plantations scattered around the southern half of the island. They're nothing compared to those in China or Japan, but if you're a fan of green tea or green tea products, then you might want to check them out sometime.
The most popular and tourist friendly is O'Sulloc, located just west of Donggwang-ri around route 1116 or just off route 95 if you're coming from Jeju-si; you can't miss the signs.
O'Sulloc is a company based out of Seoul that bought land on Jeju, and has several outlet stores and cafes within the city.
At the plantation on Jeju is a newly renovated museum, which has an interesting exhibition filled with Korean artist tea-ware along with others collected from around the world. Together with a souvenir shop and a cafe, it makes for a quaint place to sit and enjoy some green tea.
As you can see from the video, it's quite popular with tourists; so expect it to be busy during the summer season. They have a variety of tea rolled cakes, green tea lattes, earl grey tea cookies, green tea ice cream and of course, just regular green tea. Prices from 4,000 won to 8,000 won for individual items.
I decided to go with the ice cream, which was delicious.
Just past the museum are fields and fields of green tea; the weather when I went was nice enough for a pleasant stroll.
With rows upon rows of lustrous green leaves and a looming Sanbangsan in the background, it makes for an exquisite scene.
I'm not exactly sure how they harvest it all, or what the process is from growing it to drinking it in your cup, but I imagine there are guided tours available if you check with the museum reception at the entrance, or at the very least, a brochure.
There is no entrance fee to the museum or to walk around the fields, so feel free to drop by anytime during the day.