The World's Highest Marathon

The Expedition

In May 2027, a group of intrepid runners will take part in a once-in-a-lifetime challenge: to complete the highest marathon ever attempted.

The 42.2km course will start at 4,810m (above the summit of Mt Blanc) and every step will remain above 4,395 metres throughout – surpassing the world record set in 2026, which is based on the lowest point reached in the marathon.

Every participant who crosses the finish line will become a world record holder – part of a select group of runners who achieve something truly extraordinary, in one of the most extreme environments on Earth.

The expedition begins in La Paz, the highest capital city on Earth, before travelling through Lake Titicaca, the vast Uyuni Salt Flats, and into the high Andes. Along the way, participants will trek above 6,000 metres, allowing their bodies time to adapt before race day.

The marathon itself will start at 4,810 metres, where oxygen levels are just 58% of those at sea level. With every step remaining above 4,395 metres, the course will set a new world record for the highest marathon ever run.

Cold temperatures, exposed terrain, and the scale of the Altiplano make this a demanding environment. Throughout the journey, participants are supported by experienced high-altitude specialists, medics, and support teams.

Organised by BecomingX and Adventure Alternative, the 2027 expedition builds on a legacy of delivering world-first challenges in extreme environments.