Very few marathons require head torches. None that we are aware of requires 3D course mapping and safety helmets to be worn. And only one will set a Guinness World Record as the deepest marathon ever run at 1,120 below sea level (1,312m underground)!

This extraordinary event will be hosted by Boliden, owners of the Garpenberg Zinc Mine in Sweden and the headline sponsor of the World’s Deepest Marathon. The race will be organised by BecomingX and the International Council for Mining and Metals on Saturday, 25 October 2025.

The competitors are aged from their 20s to their 60s, representing over 17 countries, including CEOs of mining companies, professional services executives, environmental experts, tech entrepreneurs, charity workers and more, many running their first marathon.

BecomingX, co-founded by adventurers Paul Gurney and Bear Grylls OBE, said: "This historic endeavour captures the spirit of exploration and human resilience, and proves that limits can always be redefined. From the depths of the earth, up to 60 selected trailblazers will push beyond their physical and mental boundaries to make history in one of the most extreme environments imaginable."

Paul set up BecomingX with a singular purpose: to help people realise their potential. A passionate adventurer, he has completed two of the world’s toughest races: a 600K race to the Magnetic North Pole and the 270K Marathon des Sables. Paul has also helped raise over $5 million for charities that are focused on building skills and empowering communities.

Bear is known worldwide as one of the most recognised faces of survival and adventure. He is a former British Special Forces soldier and one of the youngest climbers to reach the summit of Mount Everest. Bear added: “Life rewards the dreamers, the go-getters, and the resilient. BecomingX helps people to understand what it really takes to succeed and gives them the skills and confidence to get out there and go for it. Every single day.”

No one has attempted a marathon at this depth before. Participants will endure temperatures of up to 30°C in total silence, running in complete darkness, with only their head torches for light. The mine tunnel is 2.4K long, and runners will complete nine complete loops. The course is 5 metres wide, with plenty of space to pass, and there is around 2% gradient, with firm gravel underfoot.

For full details, visit the World's Deepest Marathon website here.

Course graphic courtesy of Becoming X website here