Ultra Running Hub Iki, Nagasaki Pref., Japan · Saturday, October 17, 2026
Fixed Distance 100K
Iki 100 Km Ultra Marathon
44 days away
100 km Distance
not publishedn/a Climbing
5.0 est Grit · Challenging
Calculated from 100 km alone — the organiser has not published an elevation profile. Read 5.0 as a floor, not a verdict.
What the course asks
Time limit 14 hours
8:24 min/km average. Comfortable. Room to walk the climbs and stop at aid. Climbing is unpublished, so this pace is a ceiling on the effort, not a measure of it. Tighter than 85% of 100K races. Measured against 203 races of the same distance. Cut-off calculator →
Field size ~376 Large. Rarely out of sight of another runner.
DUV results for the 2025 edition (100km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.
Typical conditions, October
Daytime high 22°C
Night low 20°C
Rainfall Showers likely
Daylight 11 h 20 m of light
Regional 2001-2020 average for October — NASA POWER, grid elevation 4 m. Not a forecast.
The Aid Station
Course-specific beta from the community
With trail terrain, choose a shoe with moderate cushioning for optimal performance.
For 100km+ efforts, prioritize real food at aid stations to prevent palate fatigue.
Gear for this race
Chosen for 100 km of trail.
- Trail Running Shoes 100 km of trail — cushioning that is still there in the last quarter.
- Race Nutrition Past 100 km the palate quits before the legs do — carry more than one flavour.
- Hydration Vests Flask capacity for 100 km, without the bounce.
- Headlamps A 14 h limit puts you out there after dark.
- Accessories Chafe and blisters end more 100 km races than fitness does.
Course Notes
One big loop around Iki Island.
Similar races
Other 100K trail ultras, closest in distance first.