Lake Ossiach is close to the motorway. But again not too close! Do not forget that you need a so-called “toll vignette”. These are available at almost every gas station. There is a toll vignette for 10 days, 2 months or all year. You can get this now also Digital, in the Online Shop of the Asfinag (the Austrian motorway authority ;-))
You need a taxi? We recommend TaxiAdvisor, an independent search portal for taxis & transfers in our area. Here you will find an overview of taxis around Ossiacher See.