The short answer
Coast to Kosci is Australia's most demanding road ultra: 240km from Twofold Bay near Eden, at sea level, to the summit of Mt Kosciuszko and down to the finish at Charlotte Pass. Around 60 invited runners get 46 hours. The 2026 edition starts on 20 November.
The course is a slow argument with your equipment
Almost all of it is sealed road and hard gravel, run on legs that stop absorbing impact somewhere well before Dalgety. There is no technical ground to break the rhythm and no descent that changes the loading. It is the same footstrike, tens of thousands of times, for the better part of two days.
The conditions do change, and not gently. Coastal heat on day one gives way to alpine cold on night two. Feet can swell a full size in between. And the climb comes last, when they have.
Three requirements fall out of that
- Cushioning that has not flattened by the second night. Foam that gives up at 150km is a race-ending problem here, not an inconvenience.
- A base that holds a runner whose form has gone. By the Snowy Mountains section nobody is landing well. The platform has to do work the runner can no longer do.
- Fit you can change at a crew stop without sitting down. Swelling peaks late, in the cold, in the dark, with hands that do not work properly.
What that points to
The C1 was built against that brief: a 42mm stack, a CircleCELL top layer over a rubberised base, a wider platform with higher sidewalls, and TUNEDFIT to release the forefoot as swelling peaks while the midfoot stays locked. CircleCELL holds PEBA-level energy return for roughly twice as long as conventional foam, which is a durability claim rather than a speed one, and durability is the relevant axis over 46 hours.
Feet can swell a full size between the coast and the summit. And the climb comes last, when they have.
Use the crew
Crewed racing is an equipment advantage most runners underuse. Stage a second pair, usually half a size up, for the alpine section, and plan the change at a point on the course rather than at the point where it starts to hurt. Do the same with socks. The decision is much easier to make at 200km if it was made at a kitchen table in October.
Before you commit
Get fitted for both pairs at the same time, by someone who understands that the second pair is not simply the first pair in a bigger box. Sizing, lacing and sock combination all shift when feet have been swollen for twenty hours, and that is a conversation worth having in person.
Mount to Coast is distributed in Australia and New Zealand by Endurance Edge. Find your nearest stockist.
Common questions
How long is Coast to Kosci?
Coast to Kosci is 240km, from Twofold Bay near Eden on the NSW coast to the summit of Mt Kosciuszko and down to the finish at Charlotte Pass, with a 46-hour time limit.
When is Coast to Kosci 2026?
The 2026 Coast to Kosci starts on 20 November 2026. The race is invitational, with around 60 runners on the start line.
What shoes suit Coast to Kosci?
A cushioned, stable road ultra shoe with adjustable fit, such as the Mount to Coast C1 with its 42mm stack, wider base and TUNEDFIT dual lacing. Many runners stage a second pair half a size up for the later stages.
Is Coast to Kosci a trail race?
No. Almost all of the course is sealed road and hard gravel. It is a road ultra that finishes at altitude, which is why road ultra cushioning matters more than trail grip.
