Here are some photos from the Yeongsil trail, on the western side of Mt Halla. The trail doesn’t go to the top of Halla but climbs through woodland before emerging onto the treeless mountainside below the crater. The start is just below 1300m and the goal is the Witsae-oreum shelter at around 1700m. Much of the route is on wooden steps and walkways, roped to prevent walkers from wandering off the straight and narrow.
Weather permitting, there are views to the coast on the north, west and south sides of the island, and you can look down at the oreum-covered landscape of western Jeju.