Distance
Terrain
The Saroma Lake 100km Ultramarathon Online Challenge brings the spirit of one of Japan's pioneering ultra-marathons to runners anywhere in the world. Entrants cover 100 km under their own steam, at their own pace and on ground of their own choosing, whether that is local trails, coast paths, park loops or city streets. The challenge is modelled on the classic loop around Lake Saroma on Hokkaido's Okhotsk coast, a route known for long, open stretches and varied terrain of rugged trail and shoreline. Several packages are on offer, from a one-month challenge through to a two-month staged version and a year-end challenge, with entry levels from ¥4,990 to ¥12,990. Runners log their completed distance through the official challenge platform before the end of their chosen window. There is no starting gun and no finish line to travel to: the whole point is to feel the pull of the Saroma distance wherever you happen to be.
Online challenge based on the iconic Saroma Lake 100 km Ultramarathon
Run the distance anywhere in the world
Choose from one-month, two-month staged and year-end challenges
Varied terrain inspired by the Lake Saroma course, from rugged trails to open coastline
Complete the distance at your own pace, on your own schedule
Start / Finish
Anywhere the participant chooses (virtual challenge)
Anywhere the participant chooses (virtual challenge)
What you get
On the day
Before you enter
Other questions
No. It is a virtual challenge, so there is no fixed start line and no marked course. You cover 100 km on a route of your own choosing, in your own time, during the challenge window you signed up for. The format is designed to mirror the feel of the real Lake Saroma ultra rather than to reproduce its course.
Anywhere you like. Local roads, trail networks, park loops, coast paths or a treadmill all count, as long as you record the distance. Many entrants build the total from a series of shorter runs across the challenge window rather than one continuous effort.
The listing offers six options: a September one-month 100 km, an October one-month 100 km, a November one-month 100 km, a year-end one-month 100 km, and a two-month challenge split into Stage 1 (November to December) and Stage 2 (November to December). All of them are 100 km in total, with the difference being how much time you have to complete the distance.
No. The whole point of the online challenge is that you run wherever you are. There is no venue to travel to, no accommodation to book and no race-day logistics, though plenty of entrants use the challenge as preparation for eventually running the real Saroma Lake ultramarathon in Hokkaido.
The challenge is listed as a running event and the distance is meant to be covered on foot. Walking forms part of most ultra efforts, but if you plan to walk the bulk of your 100 km, check the organiser's rules on the official challenge page before you enter.
Entry fee
Registration isn't open yet. We'll show pricing when the organiser confirms.Kiryu, Japan
Expected October 2027
Provisional date, around Oct 7Are you the organiser of Saroma Lake 100km Ultramarathon Online Challenge (サロマ湖100kmウルトラマラソン オンラインチャレンジ【October 1month 100km】)?
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