XTERRA O-SEE Ultra Trail 100K is a trail race held on October 17, 2026, starting and finishing in Kurort Oybin in the Zittau Mountains Nature Park, Saxony, Germany — a forested sandstone ridge landscape on the Czech border. The course covers 100.2 km with 3,451 m of gain (34.4 m/km) including 35 km through the Bohemian Lusatian Mountains in Czech Republic.
The 100k distance debuted in 2025 and is the 2026 XTERRA Trail Run European Championship. A 12% distance-weighted average uphill gradient places this race in the top 10–14% of the DTR database for average climbing steepness. The biggest climb (354m, km 75) arrives after 75km already covered, with a 54.9% maximum gradient spike. Entry runs €140–160 depending on timing (€1.40/km current).
Dresden (DRS) or Prague (PRG) are both 107 minutes by road. A qualifying race of ≥75km in the last five years is required. With 84 finishers in its debut, it suits technically confident 100km runners who want a European championship race in a wooded autumn setting.