Manjanggul Lava Tube

Manjanggul in Gujwa-eup, Jeju City, is a lava tube about 7.4 km long. It was formed by lava flowing from the Geomunoreum volcano, and its passages reach up to 18 m wide and 23 m high, which puts it among the largest lava tubes in the world. After a long closure following a rockfall, it reopened on 30 May 2026, and the entire public section now has a boardwalk that makes the walk much easier.

How the cave was formed

Manjanggul is the best-known cave of the Geomunoreum Lava Tube System. It was originally one continuous tube with neighbouring Gimnyeonggul, until lava flowing inside blocked the middle and split it in two. Gimnyeonggul, an S-shaped cave about 700 m long, lies some 90 m from the lower end of Manjanggul. Both were designated a Natural Monument in 1962, and Manjanggul is a key part of the UNESCO World Heritage Site "Jeju Volcanic Island and Lava Tubes". In some places the tube runs on two or even three levels.

What to see

Visitors enter through Entrance No. 2 and can walk about 1 km. The rest of the cave is closed to protect it.

• Lava column: At the end of the public section stands a column about 7.6 m tall, built up as lava dripped from the ceiling to the floor. It is known as one of the largest lava columns in the world.
• Turtle Rock: A lava raft, a lump carried along by the flow that hardened on the floor. Seen from above, it looks like a turtle's shell.
• Walls and floor: From the boardwalk you can see lava flow lines on the walls, shelf-like lava ledges and small lava stalactites on the ceiling.

Reopening after the rockfall

On 29 December 2023, a piece of the ceiling fell near the entrance and the cave was closed. Jeju Province spent KRW 12.1 billion on a boardwalk along the whole public section and on safety structures at high-risk spots. The lighting was replaced with dimmer LEDs to reduce the green algae that grow under artificial light. Once you are down the entrance stairs, the floor is level enough for a pushchair.

Good to know

Manjanggul was made known by Bu Jong-hyu (1926–1980), a teacher at Gimnyeong Primary School. In 1946 he formed an expedition of about 30 pupils, who explored the cave in straw sandals by torchlight, with almost no equipment. 2026 marks his 100th birthday and the 80th anniversary of the discovery, and a sculpture at the entrance honours him and his young explorers.

Wildlife and three entrances

Manjanggul has three entrances, formed where parts of the ceiling collapsed. Visitors use only Entrance No. 2, which faces south; the areas around Entrances 1 and 3 are closed, and Entrance No. 3 is considered the best habitat for cave life. Of all the caves in the Geomunoreum system, Manjanggul has the greatest number of living creatures, including the Jeju cave spider, and at least 30,000 bent-wing bats have been counted above Entrance No. 2, the largest bat colony confirmed in Korea. That is one more reason not to shine lights around or make noise inside.

The closed sections are normally off-limits, but small guided programmes into them are sometimes run during events such as the Jeju World Heritage Festival. If you are interested, check the festival schedule in advance.

Tripto tips

• Temperature: It stays at about 10–15°C all year. A cool escape in summer, but bring a light jacket.
• Time: About 1 hour for the walk there and back.
• Opening: Before the reopening, the cave was open 09:00–18:00 (last entry 17:00), closed on the first Wednesday of each month, and cost KRW 4,000 for adults and KRW 2,000 for teenagers and children. Details may have changed, so check the Jeju World Heritage Office before you go. Parking is free.
• Gimnyeonggul: The neighbouring Gimnyeonggul (Gimnyeongsagul) is not open to visitors.
• Combine with: Seongsan Ilchulbong, Bijarim Forest and Gimnyeong Beach are all nearby on the east side of Jeju.