The calculated distance (air line) between Telfs and Klagenfurt am Wörthersee is approximately 160 miles respectively 257 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 Telfs and Klagenfurt am Wörthersee has been calculated here.
Air line (approximately)
257 kilometers
139 nautical miles