From Italy:

via Udine, Villach, Spittal/Millstätter See - Lendorf - Möllbrücke (Mölltal ramp) - Obervellach - Flattach

From Vienna:

take the south highway, via Klagenfurt, Villach, Spittal/Millstätter See - Lendorf - Möllbrücke (Mölltal ramp) - Obervellach - Flattach

From Germany:

via Munich, Salzburg, Spittal/Millstätter See - Lendorf - Möllbrücke (Mölltal ramp) - Obervellach - Flattach

Road tax-free journey

1) Munich - Bad Reichenhall - Lofer - Zell am See - Lend - Gasteinertal - Böckstein - car shuttle (chargeable) - Mallnitz - Obervellach - Flattach

Timetable of the Tauern car shuttle
Tauern shuttle

2) Munich - Inntaldreieck - Kufstein - St. Johann - Kitzbühel - Mittersill - Felbertauernstraße (chargeable) - Matrei -  Lienz - Iselsberg - Winklern - Obervellach - Flattach

Information about the Felbertauernstrasse