The calculated distance (air line) between Rostov-na-Donu and Labinsk is approximately 186 miles respectively 299 kilometers.
By car or train, the actual journey to Labinsk is certainly longer, as only the direct route (as the crow flies) between Rostov-na-Donu and Labinsk has been calculated here.
Air line (approximately)
299 kilometers
161 nautical miles