Lunzer See, Natural lake in Lunz am See, Austria.

Lunzer See is an oval lake about 1,600 m long and 600 m wide at 608 m elevation, lying in a deep valley below the limestone Dürrenstein (1,878 m) in the Mostviertel. Its dark grey-blue water reflects the surrounding hills; two wooden posts with green bands and a low wooden platform stand over the water near the shore. The Seebach flows through it, and the west bank holds jetties, restaurants and boat rentals.

For centuries the lake belonged to the Carthusian monastery of Gaming; after Emperor Joseph II dissolved the charterhouse in the late 18th century, it passed to the Festetics counts. Count Gabor Festetics, the last male of that line, sold most of the Lunzer See estate to the Kupelwieser family.

The Seebühne on the west shore was conceived by the Lunz artist Hans Kupelwieser. Each July it hosts wellenklänge, a summer festival of contemporary art, and the music festival more ohr less, founded by Hans-Joachim Roedelius. In winter the stage is not removed: its pontoons are flooded and sunk in the lake so that ice pressure cannot damage them.

Boat rentals and a restaurant are on the west shore, where the Seebühne stage also stands. The Biological Station Lunz, run by the University of Vienna, the University of Natural Resources and Life Sciences Vienna and Danube University Krems, occupies the east shore. The lake lies at 608 m at the foot of the Dürrenstein; the Seebach flows through it and empties into the Ybbs at Lunz.

The lake serves as the starting point for a Three-Lakes hiking route that connects it with two other water bodies at higher elevations in the Ybbstal Alps. Hikers on this trail experience dramatically different mountain views and forest settings as they move between the three lakes.