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