Iki 50 Km Ultra Marathon

Race completed

50 km Distance

not publishedn/a Climbing

2.5 est Grit · Entry level

Calculated from 50 km alone — the organiser has not published an elevation profile. Read 2.5 as a floor, not a verdict.

33.7501° N, 129.6913° E © OpenFreeMap © OpenMapTiles Data from OpenStreetMap

What the course asks

Time limit 8 hours 9:36 min/km average. Tight. Climbing is unpublished, so this pace is a ceiling on the effort, not a measure of it. Tighter than 84% of 50K races. Measured against 1057 races of the same distance. Cut-off calculator →

Field size ~204 Large. Rarely out of sight of another runner.

DUV results for the 2025 edition (50km) — 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.

Results history

Year	Race	Finishers	Men's winner	Women's winner
2025	50km	204	Yukai Ikeda · 03:44:41	Yuki Nomoto · 04:14:19
2024	50km	213	Kazuki Matsushita · 03:28:10	Yoko Yamada · 04:48:34
2023	50km	216	Keita Masuda · 03:15:15	Yuki Nomoto · 04:15:49
2022	50km	193	Shinya Abe · 03:36:59	Makiko Masushige · 04:21:46
2019	50km	179	Takanobu Oda · 03:33:14	Hiroko Shiozuka · 04:04:20
2018	50km	180	Takuya Nakamura · 03:18:44	Yuka Miyakawa · 04:38:04
2017	50km	226	Taichi Hayata · 03:21:23	Hisayo Matsumoto · 03:52:50
2016	50km	112	Ryogo Sawami · 03:37:08	Hisako Sato · 04:25:38

The field has held steady: 213 in 2024, 204 in 2025. 30% of the 2025 field were women.

DUV results for the 2025 edition (50km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.

Course notes

gear With trail terrain, choose a shoe with moderate cushioning for optimal performance.

Gear for this race

Chosen for 50 km of trail.

Trail Running Shoes 50 km of trail — cushioning that is still there in the last quarter.
Race Nutrition 50 km of self-supported fuelling between aid stations.
Hydration Vests Flask capacity for 50 km, without the bounce.
GPS Watches Battery life first — a 50 km day outlasts most full-GPS modes.

New Balance

Fuel Cell Super Comp Trail

★★★★★ 4.5

Adidas

Terrex Speed Ultra

RunRepeat found the Adidas Terrex Speed Ultra to have a grippy outsole and great lockdown, while iRunFar noted that the shoe works on a variety of trail conditi…

★★★★★ 4.5

Spring Energy

Awesome Sauce

Real food gel with 180 calories. Rice-based with natural flavors.

$4 ★★★★★ 4.6

Nathan

VaporKrar 12L

12L race vest co-designed with ultra champion Rob Krar, with insulated bladder pocket.

$170 ★★★★★ 4.6

COROS

APEX 2 Pro

GPS running watch with 75-hour GPS battery, topo maps, and training metrics.

$500 ★★★★★ 4.7

All gear guides →

Overview

The Iki 50 Km Ultra Marathon in Iki, Nagasaki Pref., Japan is a road race scheduled for October 17, 2026. This 50 km event has a cut-off tighter than 84% of 50k cut-offs, which means runners need to maintain a pace faster than 9.6 minutes per kilometer to finish.

With 204 finishers in its 2025 edition, the race field is bigger than 91% of 50k fields. This event has been held 8 times since 2016, with the most recent edition in 2025.

Similar races

Other 50K trail ultras, closest in distance first.