2,000 runners to tackle Seoul's mountains, streets in 2026 Seoul100K
Participants in the 2025 Seoul International Ultra Trail Running Race run at Gwanghwamun Square in Seoul, Sept. 20, 2025. Courtesy of Seoul Metropolitan Government
Seoul will turn its mountains, fortress walls, riverfront and downtown streets into a single endurance course this weekend as 2,000 runners from Korea and abroad take part in the 2026 Seoul International Ultra Trail Running Race, known as Seoul100K.
The seventh edition of Seoul 100K runs Saturday and Sunday, with 170 international participants from 36 countries joining professional athletes, running clubs and residents across 100K, 50K and 20K events.
The 100K and 50K races start at 5 a.m. Saturday from Gwanghwamun Square, while the 20K race begins at 7:30 a.m., sending runners toward destinations including Mount Inwang, Mount Bukhan, the Han River and Cheonggye Stream.
Organizers have positioned the race as an urban trail-running event that combines Seoul's natural landscapes with its historic and modern cityscape, with the 100K course allowing runners up to 31 hours to complete the route.
Among the international competitors are Sweden's Petter Engdahl, Switzerland's Jasmin Nunige and Germany's Marcel Höche in the 100K, while Norway's Nora Serres, Britain's Holly Page and American Stephen Kersh are entered in the 50K.
This year's race also introduces what organizers describe as Korea's first national park coexistence section for trail running, with participants required to walk or move slowly through part of Mount Bukhan and give priority to other hikers.
The section will not count toward race rankings, though runners will receive overall race records that can be used for UTMB Index and International Trail Running Association points.
Safety measures include 15 race medics, rescue personnel on major mountain sections, medical staff and ambulances at checkpoints, and a joint emergency operations center involving police and firefighters.
Seoul100K bridges the city's mountain trails directly with its bustling downtown, offering runners a seamless trek through Korea's natural and historical landmarks.
Cho Seong-ho, director general of the city’s Tourism and Sports Bureau, called it a signature event designed to cultivate a "mindful trail-running culture" while drawing athletes from around the globe.
"Seoul100K is a signature event that connects Seoul’s iconic mountains with its vibrant downtown, allowing participants to experience our nature, history, culture, and modern skyline all in a single course," said Cho. "We aim to cultivate a mindful trail-running culture that respects both nature and fellow hikers, while elevating this into a premier international sports event that draws trail runners from across the globe."
This article was published with the assistance of generative AI and edited by The Korea Times.