The calculated distance (air line) between Sri Jayewardenepura Kotte and Bentota is approximately 32 miles respectively 52 kilometers.
By car or train, the actual journey to Bentota is certainly longer, as only the direct route (as the crow flies) between Sri Jayewardenepura Kotte and Bentota has been calculated here.
Air line (approximately)
52 kilometers
28 nautical miles