Just west of the city, the Wörthersee is a long, narrow alpine lake set in a green basin between the Karawanken to the south and the Sau Alps to the north. Sixteen kilometres long and remarkably warm by Austrian standards — water temperatures in July and August often reach 25°C — it is the centre of Carinthian summer life.
A paved cycle path runs almost the whole way around the lake, and ferries link the resorts of Velden, Pörtschach and Maria Wörth in season. The Strandbäder along the shore charge a modest entry fee and offer changing rooms, lawns and diving platforms. Klagenfurt's own beach, the Strandbad Klagenfurt, sits at the eastern tip and is a short bus ride from the centre.