Myeongjin Jeonbok

Bijarim Forest

Two loops split at a crossroads inside the wood. Course A is about 2.2 km of level volcanic-cinder path, 40 minutes to an hour, and takes a pushchair or wheelchair with help on the slopes; course B includes rough stone and does not. Dogs are not admitted, which separates this from most Jeju walks.

Manjanggul Lava Tube

A lava tube about 7.4 km long whose main passage runs 18 m wide and 23 m high. Roof collapses left three entrances; visitors may use only the second, and may walk 1 km in from it. At the end of that kilometre stands a lava column about 7.6 m high, said to be the largest known anywhere, and that column is also where you turn round. The operator files this cave as partly open — the other caves inscribed with it are closed to the public altogether.

Udo Island

The ferry controls the whole day: photo ID is a legal requirement to board, not a formality, and outside vehicles are barred from the island until 31 July 2029 apart from named exceptions. Plan around the last sailing back, and note the island charges its own park admission on top of the fare.

Seongsan Ilchulbong Tuff Cone

Two separate walks share the site: a ticketed climb to the summit, 30–40 minutes of stairs, and a free coastal path around Umutgae with a much gentler gradient. The monthly closure is the thing that ruins trips — it is the first Monday, not a holiday pattern anyone guesses.