The calculated distance (air line) between Munich and Klagenfurt am Wörthersee is approximately 165 miles respectively 266 kilometers.
By car or train, the actual journey to Klagenfurt am Wörthersee is certainly longer, as only the direct route (as the crow flies) between Munich and Klagenfurt am Wörthersee has been calculated here.
Air line (approximately)
266 kilometers
143 nautical miles