The calculated distance (air line) between Nakhon Ratchasima and Chanthaburi is approximately 163 miles respectively 263 kilometers.
By car or train, the actual journey to Chanthaburi is certainly longer, as only the direct route (as the crow flies) between Nakhon Ratchasima and Chanthaburi has been calculated here.
Air line (approximately)
263 kilometers
142 nautical miles