The Weissensee is a bathing lake in the Austrian state of Carinthia within the Gailtal Alps. It shares its name with the municipality of Weissensee on its northern and southern shore.
Despite its elevation of 930 metres (3051 ft), the waters can reach 24 degrees Celsius in the summer months, while in winter the water freezes over completely and allows skaters to move freely on the ice.
About two thirds of the lake's surface are part of a protected area. Except for public transport, the operation of motor boats is prohibited. The waters of the lake reach drinking water quality. The area is full of wildlife. It contains many different types of fish, especially trout, common carp, perch and northern pike. Also, there are many different birds, ranging from ducks to geese and herons.