XTERRA O-SEE Ultra Trail 50K is a UTMB Index-certified trail race held annually in October in Oybin, Germany, within the Zittau Mountains Nature Park at the tripoint of Germany, Poland, and the Czech Republic. The loop course covers 50.5km and 2,022m D+ through forest and sandstone terrain, starting and finishing in Oybin village beneath the ruins of a medieval monastery. In 2026, the race hosts the XTERRA European Trail Run Championship for the 50K and 25K distances, with qualification slots to the 2027 XTERRA Trail Run World Championship for top finishers.
Average uphill gradient ranks 171st of 390 European ultras -- above average for steepness -- while the course's distributed climbing profile (Top1 Ascent 251m, ranking 319/390) reflects frequent short steep pitches rather than one dominant sustained climb. Entry from 80 EUR (current tier, no platform fees). Not sold out; the 100K companion distance is fully booked. Nearest airports: Dresden (DRS) and Prague (PRG), each 1.75 hours by car. Limited accommodation in the Zittau region; book early. First edition: 2019.