The calculated distance (air line) between Hainburg an der Donau and Klagenfurt am Wörthersee is approximately 162 miles respectively 261 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 Hainburg an der Donau and Klagenfurt am Wörthersee has been calculated here.
Air line (approximately)
261 kilometers
141 nautical miles