Starnberger See Längsdurchquerung Seeshaupt–Percha

In February 1929, the frozen surface of the lake became an unlikely laboratory for speed when rocket pioneer Max Valier launched his sled, the Rak BOB II, reaching 400 km/h in front of the Undosa bathhouse. This display of mechanical ambition contrasts sharply with the silent, rhythmic strokes of swimmers covering the 19,700 meters of the Starnberger See Längsdurchquerung. While the historic Undosa wave pool remains a visual anchor from the water, reminding onlookers of the lake's early 20th-century status as a fashionable resort, the challenge today is a point-to-point test of pure endurance. Swimmers crossing the basin pass over depths that hold secrets of a vastly different era, including the Roseninsel, where archaeological excavations have recovered bronze fish-hooks and dugout canoes dating back three millennia.

Navigating the deep basin

As you progress through the center of the lake, you are swimming above the Allmannshauser Steilwand. This is the deepest and steepest underwater wall in German inland waters, plunging sharply to 70 meters and extending toward the lake's deepest point; it is a feature that usually commands the attention of technical divers, but here it defines the sheer scale of the environment beneath your chest. The surrounding topography, characterized by glacial terminal moraines and the distant silhouette of the Ilkahöhe, provides a constant reference point for navigation. Those who find their rhythm here often look to extend their season; if you are considering further tests of stamina in the region, you might explore the Seeüberquerung from Tutzing to Ammerland, which offers a different perspective on these protected waters. The lake’s identity is steeped in royal history, once home to the opulent Bucentaur, a state barge used by Elector Ferdinand Maria for elaborate courtly festivals. Today, the water remains a vital resting place for thousands of migratory birds, and the event draws its character from the legacy of the 1908 German Swimming Championships held on these same shores. Participation is supported by strict logistics to manage the 19.7km route, ensuring safety across the open expanse. Wetsuits are permitted for all athletes, providing an essential layer of comfort during the long-distance effort.