The calculated distance (air line) between Lapinlahti and Lappeenranta is approximately 161 miles respectively 260 kilometers.
By car or train, the actual journey to Lappeenranta is certainly longer, as only the direct route (as the crow flies) between Lapinlahti and Lappeenranta has been calculated here.
Air line (approximately)
260 kilometers
140 nautical miles