Arc Of Attrition 100 Mile Ultramarathon

UTMB Arc of Attrition 100 Ultra Marathon

Welcome to one of the most unforgiving, brutal and breath taking ultramarathons in Europe. Now a proud part of the UTMB World Series, the Arc of Attrition 100 is an extreme 100 mile coastal ultramarathon held in the depths of the British winter.

This is not a race for the faint-hearted. Taking you along a spectacular and punishing section of the South West Coast Path in Cornwall, the "Arc" demands absolute respect. With its combination of relentless elevation, technical rocky terrain, deep coastal mud and the high probability of severe winter weather, finishing this race is a monumental badge of honour in the global ultra-running community.

Course

The route takes runners on a spectacular point-to-point journey around the rugged "arc" of the Cornish peninsula.

• The Terrain: Do not let the phrase "coastal path" fool you into thinking this is a flat beach run. The South West Coast Path is notoriously jagged. You will be subjected to thousands of steep, irregular stone steps, narrow cliff-edge trails, slippery rocky coves and energy-sapping bogs.
• The Elevation: Over the course of 100 miles, the constant drops into small fishing villages and immediate, brutal climbs back up to the clifftops result in a staggering accumulation of elevation gain of 5,500+ metres, rivalling many mountainous alpine races.
• The Night Shift: Because this event takes place in deep winter (typically January), the days are short. You will spend up to 14 hours running in complete darkness, navigating the technical cliff paths by the solitary beam of your headtorch while battling the roaring Atlantic winds.

UTMB Running Stones

As an official UTMB World Series event, the Arc of Attrition operates to world-class standards while retaining its uniquely gritty Cornish soul. Completing the 100 mile distance earns you highly coveted UTMB Running Stones, which are essential for entering the lottery for the UTMB World Series Finals in Chamonix.

Because of the severe, exposed nature of the Cornish coastline in winter, you cannot enter the 100 mile event without proving your experience. Entrants must meet strict qualification criteria, usually involving previous finishes at 100km or 100 mile ultramarathons.

Are you ready to face the winter beast? Dial in your winter kit, master the coastal steps and prepare for an unforgettable 100 mile journey. For the most up-to-date entry criteria, exact dates and to register for the ballot, please visit the official Arc of Attrition UTMB website.

Want to know what it really takes to conquer the Cornish coast in the dead of winter? Check out our exclusive race report from the 2026 Arc of Attrition 100 to read about all the action from this year's brutal event.