XTERRA O-SEE Challenge Olbersdorf

Cross-Triathlon in the Zittauer Gebirge

Cross-triathlon is the wild, off-road sister of classic triathlon: instead of road bikes, there are mountain bike singletracks, and instead of road running, there's a trail run through the terrain. The venue for Germany's largest event in this discipline has been Olbersdorfer See since 2000, a renatured open-cast mine remnant in the Zittauer Gebirge Nature Park — in the state of Saxony, Görlitz district, on the border with Poland and the Czech Republic (the border triangle). From August 14th to 16th, 2026, the O-SEE Challenge will take place there for its 26th edition. Since 2004, it has been part of the worldwide XTERRA series, a cross-triathlon competition series recognized by World Triathlon with stops in the USA, Brazil, Italy, Sweden, among others.

Three Days, Many Categories

Several parallel competitions take place over three days. The highlight is the XTERRA distance (German Championship) with 1.5 km swimming, 30 km mountain biking, and 10 km trail running — a tough challenge lasting about 2.5 to 3.5 hours. The O-SEE Classic is the popular sports distance for individual starters and teams (1 km / 21 km / 6 km). There is the shorter O-SEE Reduced, the O-SEE Light/Family for beginners, and the O-SEE X'Kids in four age groups for children and youth. An O-SEE Team Sprint and the Retro format round off the program. A total of about 1,500 athletes will start, from international top triathletes (e.g., Branden Currie, Sam Osborne, Lesley Paterson) to hobby athletes from the region.

Swimming, Mountain Biking, Trail Running

The swimming takes place in Olbersdorfer See, a 60-hectare, crystal-clear mountain lake with good water quality (drinkable). The mountain bike course leads through the sandstone forests of the Zittauer Gebirge — singletracks, root passages, technical descents on granite and sandstone. The trail run partly leads over the famous rock formations around the Oybin mountain and along Olbersdorfer See. Overall, the course is one of the most scenic and technically demanding on the international cross-triathlon calendar.

Family Festival and Lifestyle

The O-SEE Challenge is more than a competition — it's "a summer sports festival for the whole family," as the organizers call it. On the festival grounds at Olbersdorfer See, there are food trucks, stage programs, massage services, brand booths (sports equipment and bike manufacturers), and a children's program parallel to the X'Kids races. Registration for 2026 has been open since February 2nd; early bird rates are valid until May 31st. With "O-SEE Flex" (+ €20), participants can secure flexibility: postpone start, change distance, or transfer starting place — without a penalty fee.

Location and Travel

Olbersdorfer See is located directly in the Zittauer Gebirge, just under 3 km north of the town of Zittau (border triangle Germany–Poland–Czech Republic). The region is ideal for a multi-day stay: Oybin mountain with its castle and monastery ruins, viewpoints like the Lausche summit, picturesque Umgebinde houses in the villages, and the Polish Karkonosze National Park as well as the Czech Lužické hory are in the vicinity. Hotels and holiday apartments in Olbersdorf, Zittau, Oybin, and Großschönau.