The Woerthersee is an alpine lake in the southern Austrian state of Carinthia.
The lake is elongated, about 20 km long and 1–2 km wide. It stretches from the Carinthian capital Klagenfurt in the east to Velden in the west. It is flanked to the north and south by steep alpine foothills covered with dense forests, beyond which snow-capped alpine peaks are visible. The lakes water is a distinctive blue-green colour and transparent.
The Mediterranean climate and clean, warm water make the lake a popular tourist destination in summer. Although the region around the lake has been termed Austrias Monte Carlo, in recent decades tourism around Lake Wörthersee has suffered from tough competition from package holidays to cheaper overseas destinations. As a response a number of local businesses have tried to focus on niches such as high quality tourism, family tourism or golf and horse-riding vacations.
Most tourists visit the Lake in the months of July and August when water temperatures reach 25°C. A large proportion of visitors return every summer and some own or rent holiday homes along the shore. The vast majority of visitors come from Vienna, northern Germany and the Netherlands. The largest Volkswagen and Audi car show in Europe is held here (usually May) every year and since 1981.