Zegama-Aizkorri 2026: The Complete Guide to the World's Hardest Mountain Marathon
Everything about Zegama-Aizkorri 2026: 42.2 km, 5,400m D+, May 17, 25th anniversary. Lottery entry, Golden Trail World Series, training and travel guide.
Some races are run. Some are suffered, respected and remembered for life. Zegama-Aizkorri belongs firmly in the second category.
Every May, a village of barely 1,500 inhabitants in Gipuzkoa becomes the global epicentre of mountain running for 24 hours. The world's best athletes compete on a course that shows no mercy: 42.2 km with over 5,400 meters of positive elevation gain through the peaks of the Aizkorri massif in the Basque Country. The name says it all: from Zegama to Aizkorri, and back.
ℹ️ Last verified: March 2026. The 2026 edition — the 25th anniversary — takes place on May 17, 2026. Always check zegama-aizkorri.com for the latest registration and entry details.
Zegama-Aizkorri is a mountain marathon — not a standard trail race. It's a brutal point-to-point-and-back course that starts and finishes in the village of Zegama (Gipuzkoa, Basque Country, Spain). The race climbs to the summit of Aizkorri (1,528 m), the highest peak in Gipuzkoa, and crosses some of the most technical and demanding terrain in Basque mountain running.
First held in 2002, Zegama-Aizkorri was born from the passion of local mountain runners in the Basque Country. Within a decade, it had become the most prestigious mountain marathon in the world.
The race is a core event of the Golden Trail World Series (GTWS), the planet's most prestigious circuit for skyrunning and mountain racing. Other GTWS events include Sierre-Zinal and Dolomites SkyRace.
The 2026 edition celebrates the 25th anniversary with a special initiative — "Hamaika" (Basque for "eleven") — that distributed 25 extra bibs to athletes with remarkable loyalty to the race.
Notable past winners:
Kilian Jornet (multiple wins, course record holder)
Maite Maiora (dominant women's champion)
Stian Angermund, Bart Przedwojewski, Rémi Bonnet
Women: Sheila Avilés, Ruth Croft, Judith Wyder
Course record (check zegama-aizkorri.com for current records — they are updated frequently).
Top athletes in the GTWS standings receive guaranteed or priority entry. This path is for elite and semi-elite runners who compete on the GTWS circuit.
A limited number of bibs are available via public lottery. Registration for the lottery typically opens in the autumn or early winter before the race. Check zegama-aizkorri.com for the exact dates.
To participate, you must have demonstrated experience in demanding mountain races. The race organization may verify prior results.
⚠️ There is no walk-up registration on race day. You must secure your entry in advance through the official channels.
The race starts and finishes in the village of Zegama and climbs to the summit of Aizkorri (1,528 m) via the iconic ridges of the massif.
Key points:
Start: Zegama village (approx. 400 m altitude)
Aizkorri summit (1,528 m): highest point of Gipuzkoa
Aratz (1,443 m): second major summit
Aloña (~1,300 m): technical ridge section
Finish: Back in Zegama
The terrain is notoriously technical: rocky ridges, steep grass slopes, muddy paths. In wet conditions (common in May), the rocks become extremely slippery. Fog and wind on the ridges are frequent.
Time limit: Typically around 7-8 hours (check official regulations). This is an elite and semi-elite race — the course demands serious mountain experience.
May in Gipuzkoa is cool and often wet. Expect: 10-18°C at valley level, 2-8°C on the ridges. Rain is common. Snow on the summit is possible in early May. Waterproof mandatory gear is non-negotiable.
Zegama-Aizkorri has an atmosphere unlike any other mountain race. The entire village turns out — families, children, elderly locals all lining the streets to cheer runners through. The atmosphere at the finish line, with Basque folk music and thousands of spectators, is electric.
For many elite runners, winning Zegama is the career highlight above all others. For amateur participants who manage to secure a lottery spot, finishing is a life achievement.
Regardless of event type, these training principles apply:
Aerobic base: At least 3-4 months needed for a solid aerobic base. Weekly key sessions: one long run, one tempo/threshold session, and active recovery.
Hill training: For mountain events, specific work on ascents and descents is essential. Eccentric quad strength is critical for downhill running.
