The calculated distance (air line) between Thalwil / Dorfkern and Lugano is approximately 90 miles respectively 146 kilometers.
By car or train, the actual journey to Lugano is certainly longer, as only the direct route (as the crow flies) between Thalwil / Dorfkern and Lugano has been calculated here.
Air line (approximately)
146 kilometers
79 nautical miles