Quit whining about the heat — just walk into Manjanggul
even in the height of summer
Hi, I'm GYULI, the tangerine sprite who's lived on Jeju's oreum for a hundred years. Today I want to talk about a place almost every Jeju local has heard the name of at least once — Manjanggul. If you head toward Gujwa-eup in Jeju City, you'll run into this name on signposts pretty often, though plenty of people have never actually stepped inside. I've spent a hundred years living up on the oreum with the wind, so honestly, even walking down into the ground felt a little unfamiliar to me at first. Today I want to slowly walk you through this lava tube that people say gets especially busy in summer. If you're worn out from the heat, stick around to the end.
A Lava Tube Hidden Underground in Gujwa-eup, Jeju City
Manjanggul is a lava tube located in Gujwa-eup, Jeju City. The name is familiar, but explaining exactly what it is makes me a little careful, too — it's said to have formed long ago when lava flowing down from the slopes of Mt. Hallasan cooled and hardened. Lava tubes aren't something you run into every day, so when I first heard the name, I honestly just assumed it was 'some cave or other.' Turns out it's a lot more special than that. According to what's passed down, the outer surface of the flowing lava cooled and hardened first, while lava kept moving through the inside, eventually leaving a hollow passage behind. Hearing that story makes it feel strange all over again that a path like this exists underground. I've heard there are several lava tubes scattered around Jeju, but Manjanggul is the name that seems to come up the most.
Manjanggul is said to be part of the area registered on the UNESCO World Natural Heritage list under the name Jeju Volcanic Island and Lava Tubes. I can't walk you through every detail of exactly which criteria or boundaries are involved, but multiple sources consistently describe it as one of Jeju's representative natural heritage sites. Even for someone like me, who's lived a hundred years up on the oreum, this cave's story always feels a little special. I've spent my whole life up above ground, in the wind, so knowing there's a space like this underground, carrying so much time within it, feels both surprising and oddly reassuring. Learning about this cave reminded me all over again that Jeju isn't just an island made of sea and oreum.
Having lived a hundred years only above ground, I'm still amazed that a world this big exists underground.
— 🍊 GYULIOnly Part of It Is Open, They Say — And It's Cool Inside
Manjanggul is said to be quite long overall, but I want to be careful about naming an exact figure. Different sources describe it a bit differently, and I haven't walked the whole thing myself to measure it. What I can say for sure is that the section open to regular visitors is said to be only part of the whole. The rest is reportedly kept closed for reasons like preservation or safety. So it's worth knowing ahead of time that visiting Manjanggul doesn't mean seeing the entire lava tube. I'm trying to be careful not to guess at the parts I'm not sure about. For exact details on the open section or distances, it's best to check again right before you go.
There's also a reason Manjanggul comes up so often in summer — it's said to be cool inside. Even when it's sweltering outside in the middle of summer, stepping into the cave is said to bring a noticeably cool feeling. Hearing that made it click for me why so many people head there every summer. It's said to be a different kind of cool from air conditioning — a coolness that comes from deep underground, and just imagining it feels refreshing. That said, the temperature difference between inside and outside is apparently significant, so I'll circle back to that in the tip below. That moment of stepping from blazing sun into cool cave air feels, to me, like reason enough to visit Manjanggul.
Why Manjanggul Is Worth Remembering in Summer
Personally, I find myself bringing up this story every summer. It's the season when every tourist spot gets crowded and standing in line under the blazing sun gets exhausting. Having a place where you can head underground, feel that cool air, and walk slowly feels like a genuinely welcome option at times like that. There's also the distinct atmosphere a cave space brings on its own. Looking at the old rock and walls revealed under the lighting, you can sense how much time this space holds, even without anyone explaining it in words. It's a completely different kind of trip from a crowded beach or café street, so it feels especially suited to a day when you want to walk somewhere quiet.
Still, I'd recommend always double-checking the exact details. I don't want to claim I know everything in this piece, including the parts I'm not fully sure about. Information like the open section or operating hours can change often, so checking again right before your visit is the most accurate approach. What I can say with confidence is just these three things: this cave is in Gujwa-eup, Jeju City, it's a lava tube, and it's said to stay cool even in summer. Remember just these three, and you'll still come away understanding why Manjanggul's name comes up every summer.
GYULI's Tip · Manjanggul is said to be cool inside, so even in peak summer, it's worth bringing a light jacket. The cave floor may be uneven, so wear comfortable shoes too, and double-check the open section and visiting details right before you go.