Trail running course through mixed terrain in Jeju, KR

TransJeju by UTMB 20K

20 km·508m gain·Jeju City

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Distance20 km

Gain508m

Date2 Oct 2026

Difficulty2/5

About This Race

The 20-kilometer course introduces runners to Jeju's volcanic terrain with 508 meters of elevation gain. This 1 Running Stone event offers an excellent opportunity for newer trail runners to experience the island's distinctive landscape.

Location

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Practical Info

Nearest Airport

CJU - Jeju International Airport

Best For

experienced_ultrarunnersmountain_runnersinternational_competitors

Notable Features

TransJeju offers a rare opportunity to run through a UNESCO World Heritage volcanic landscape, featuring dramatic elevation changes from sea level to South Korea's highest peak. The event showcases extraordinary biodiversity across multiple climate zones, from subtropical coastal areas to subarctic mountain forests, all within a single island setting.

Other Distances at This Event

60 km

The route explores Hallasan's volcanic terrain through a combination of established national park trails and paths that wind between the island's numerous oreum formations. Runners navigate through sections of subtropical forest before emerging onto more exposed volcanic landscape, with the course design emphasizing Jeju's geological character. The mixed terrain includes both runnable stretches and technical sections over volcanic rock, requiring attention to footing throughout. The course takes advantage of Jeju's compact geography while showcasing the environmental diversity that earned the island its UNESCO recognition. Trail surfaces vary from packed earth to volcanic stone, with some sections following traditional paths used by Jeju residents for centuries. The routing through multiple elevation zones means runners experience different microclimates and vegetation patterns within the same race.

104 km

The 104K course moves through Jeju Island's diverse volcanic terrain, with runners experiencing the full range of ecosystems that make this UNESCO site distinctive. The route incorporates technical sections across basalt formations, the island's characteristic volcanic rock that requires careful foot placement and sustained concentration. Vegetation transitions from coastal subtropical forests through temperate zones, with temperature and exposure varying significantly depending on elevation and proximity to Hallasan.

148 km

The course circumnavigates Hallasan volcano, moving through multiple climate zones as runners gain and lose elevation repeatedly around the mountain's flanks. Volcanic rock sections require technical navigation, while forested passages offer brief respite before the next climb. Water and aid stations are positioned strategically, but runners should expect extended self-sufficient sections given the remote nature of portions of the route.