The calculated distance (air line) between Sai Buri and Nakhon Si Thammarat is approximately 165 miles respectively 265 kilometers.
By car or train, the actual journey to Nakhon Si Thammarat is certainly longer, as only the direct route (as the crow flies) between Sai Buri and Nakhon Si Thammarat has been calculated here.
Air line (approximately)
265 kilometers
143 nautical miles