The calculated distance (air line) between Dehiwala-Mount Lavinia and Puttalam is approximately 83 miles respectively 133 kilometers.
By car or train, the actual journey to Puttalam is certainly longer, as only the direct route (as the crow flies) between Dehiwala-Mount Lavinia and Puttalam has been calculated here.
Air line (approximately)
133 kilometers
72 nautical miles