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TransJeju by UTMB
148km148104km10461km6120km20

Jeju 20K

UTMB World Series
20.0km·508m+
October 3, 10:00 AM
Gasiri Horse Park,
South Korea
utmb·source

Race Pace Calculator · GPX Analyzer · Trail Finder

Other races: South Korea

Read

  • How to Taper for a Marathon, Half Marathon or Ultra
  • Types of Runs and What Each Workout Actually Trains
  • Hill Training for Trail Runners: Train the Descents

Jeju 20K · Race profile

Distance
20.0km
Gain
508m+
FlatKM
22.3
Max
459m
Min
213m

About Jeju 20K

Jeju 20K is the 20.0km trail race at TransJeju by UTMB 2026 (Gasiri Horse Park, South Korea). The race starts on October 3, 2026 at 10:00 AM. It starts in Gasiri Horse Park. The time limit is 4 h.

Race strategy

Run the climb at race pace, build your speed on the downhill, and go all out at the finish.

  • Start easy and control your HR up to 8.0km.
  • Hold your race pace up to 8.8km, but stay in control.
  • Final 357m descent. Save your legs to go all out on it.
  • Ease into the early runnable section, then run your race pace, and start the final descent from 8.8km under control, then go all out near the bottom.
  • Start · 0.0km–1.8km · Race-day nerves push your heart rate up: don't follow the crowd, find your own rhythm.
  • Settle in · 1.8km–8.0km · Ease in: hold back more than feels necessary. The race is still ahead. Running pays off here: run wherever you can.
  • Work · 8.0km–8.8km · Climb of 123m, high point 460m. This is where the race is built: steady, solid effort. Climb by heart rate or breathing, not pace.
  • Home · 8.8km–19.2km · Descent of 357m averaging 3%. Build to the finish: leave whatever you have left out on the course. Very long descent: first half under control, then even, let go only near the end.

Course

The course climbs 508m+. With 25m/km of climbing, this is a rolling, mostly runnable course. By gradient, 11% of the distance is uphill, 27% downhill and 61% flat. The longest climb runs 0.8km at an average 14.8% grade (123m of vertical). The longest descent runs 10.4km at an average 3.4% grade (357m of vertical). The steepest descent drops at 24.2% over 0.3km. Surface: 53% trail, 24% road, and 7% smooth. Flat-equivalent effort: 22.3 FlatKM.

Poles

The course is runnable enough that trekking poles are not needed.

Quad damage

There is too little runnable descent to damage the quads: plan the race around climbing and fuelling.

  • Ease into the early runnable section, then run your race pace, and start the final descent from 8.8km under control, then go all out near the bottom.
  • 8.8–19.2 km · 357 m D−, -3.4% · 0.0 km ahead → even, first half under control, let go at the end

Weather

On race day, start temperatures have historically ranged from 18°C to 24°C, with around 20°C at the highest point; the chance of precipitation is about 29%. Heavy rain of 10.0mm or more falls on about 10% of days around this date.

Results

1,656 finishers completed the 2026 edition. Men's winner: Ryunosuke Omi (Japan) in 1:17:45. Women's winner: Mijung Jang (South Korea) in 1:44:50.

This page has the full results and splits, a pacing and nutrition planner, a gradient matrix, an interactive elevation profile and historical weather for Jeju 20K.

Other distances of TransJeju by UTMB 2026Jeju 100M (148km)·Jeju 100K (104km)·Jeju 60K (61.0km)

Other editions of Jeju 20K2027

Official websitetransjeju.utmb.world