The calculated distance (air line) between Kobarid and Šentilj v Slov. Goricah is approximately 103 miles respectively 166 kilometers.
By car or train, the actual journey to Šentilj v Slov. Goricah is certainly longer, as only the direct route (as the crow flies) between Kobarid and Šentilj v Slov. Goricah has been calculated here.
Air line (approximately)
166 kilometers
89 nautical miles