The calculated distance (air line) between Sv. Ana v Slov. Goricah and Koper is approximately 127 miles respectively 204 kilometers.
By car or train, the actual journey to Koper is certainly longer, as only the direct route (as the crow flies) between Sv. Ana v Slov. Goricah and Koper has been calculated here.
Air line (approximately)
204 kilometers
110 nautical miles