Mayrhofen Ultraks Zillertal Z101 is a 101 km trail race held in September in Tyrol, Austria. The course gains 7,600 m over 101 km (75.2 m/km), starting Friday at 5:00 pm from Mayrhofen and running overnight through the Zillertal and Tux Alps. Entry costs €215 (from January 1, 2026), equivalent to €2.13 per kilometre. The 2026 edition is sold out with no waiting list offered.
The race's final descent drops 2,134 m back to Mayrhofen — the 3rd largest single descent of 386 European trail distances in the DTR database. At 75.2 m per kilometre, Z101 is the 33rd most elevation-dense of 389 European distances with GPS data. Maximum field size is exactly 101 runners — one of the smallest caps on any 100 km race in Europe. The course is not additionally marked; runners navigate by GPS on signposted hiking trails. Nearest airport is Innsbruck (INN), 65 minutes by car.
Founded in 2019 and now in its seventh edition, Z101 carries 5 ITRA points — the maximum. Historical finish rates have been below 50%; the 2025 edition was cancelled mid-race due to snow at 2,000 m+. It suits elite-experienced trail runners seeking a technically demanding, low-numbers alpine challenge with genuine attrition risk.