18th O-See-Triathlon Uelzen

18 Years of Triathlon Tradition

Since its premiere in 2009, the O-See-Triathlon Uelzen has become a firm fixture in the North German triathlon calendar. 2026 will see the 18th edition — on Sunday, May 31, at Oldenstädter See. The organizer is Post-Sportverein Uelzen e.V., one of the most traditional sports clubs in the Hanseatic city. Race director is Markus Hecker, who has shaped the event for many years.

DTU-Listed Event

The O-See-Triathlon is DTU-listed (German Triathlon Union), meaning the courses are measured, competition rules are adhered to, and results are officially counted. This makes it a serious competition for both amateur and ambitious athletes. The DTU event calendar lists the event as a Middle Distance, Olympic, and Sprint Triathlon, as well as an Aquabike.

Four Distances for All Levels

The range of distances makes the O-See-Triathlon accessible to athletes of all levels:

• Middle Distance (MD): 1.9 km swim + 90 km bike + 20 km run — the most demanding competition, comparable to half distance / Ironman 70.3
• Olympic Distance (OD): 1.5 km swim + 40 km bike + 10 km run — the classic Olympic distance
• Sprint Distance: 0.75 km swim + 20 km bike + 5 km run — ideal for beginners and power athletes
• Aquabike: swim + bike (without run) — an alternative for triathletes with running injuries or as an entry-level option

Swimming in Oldenstädter See

The swim takes place in Oldenstädter See — a clear lake on the outskirts of the Hanseatic city of Uelzen. Water temperature at the end of May is usually within the range requiring wetsuits (note DTU regulations). The swim course is marked with buoys, and a sufficiently large transition area is set up in Haspelweg.

Bike Course Through the Heath

The bike course leads through the typical landscape of the Lüneburg Heath — passing through the villages of Emmendorf, Jastorf, Klein Hesebeck, Oetzendorf, Masendorf, and Molzen. The course is predominantly flat with gentle undulations, ideal for triathlon speeds. Beautiful views of heathland, forests, and fields accompany the athletes. Traffic is regulated during the competition.

Run Course Around the Lake

The run course circles the Oldenstädter See multiple times and follows adjacent paths — flat terrain, good atmosphere from spectators along the route. The finish line is in the transition area by the lake — a crowning moment for every finisher.

Atmosphere and Organization

The O-See-Triathlon is characterized by a family-friendly atmosphere. Unlike large events with thousands of participants, this event remains manageable — making logistics simpler and the experience more personal. Post-SV Uelzen mobilizes a dedicated team of helpers to ensure a smooth process.