The Upper Sûre Lake (Lac de la Haute-Sûre) stretches for about 14 km through the forested valleys west of Kaundorf, its indented shoreline creating a series of bays and inlets that make it feel wilder than its modest size. The water is clear and cold even in summer, and the lakeside paths are quiet except on July and August weekends.
Kayaks, canoes, and paddle boards can be rented at several points along the lake, particularly near Lultzhausen and Insenborn. There are designated swimming areas at Liefrange and Insenborn, both with car parks and some basic facilities. Fishing permits for the lake are available from the commune offices.