The calculated distance (air line) between Sri Jayewardenepura Kotte and Galle is approximately 61 miles respectively 99 kilometers.
By car or train, the actual journey to Galle is certainly longer, as only the direct route (as the crow flies) between Sri Jayewardenepura Kotte and Galle has been calculated here.
Air line (approximately)
99 kilometers
53 nautical miles