The calculated distance (air line) between Lauttasaari and Lappeenranta is approximately 129 miles respectively 207 kilometers.
By car or train, the actual journey to Lappeenranta is certainly longer, as only the direct route (as the crow flies) between Lauttasaari and Lappeenranta has been calculated here.
Air line (approximately)
207 kilometers
112 nautical miles