The calculated distance (air line) between Damnoen Saduak and Chanthaburi is approximately 158 miles respectively 254 kilometers.
By car or train, the actual journey to Chanthaburi is certainly longer, as only the direct route (as the crow flies) between Damnoen Saduak and Chanthaburi has been calculated here.
Air line (approximately)
254 kilometers
137 nautical miles