The calculated distance (air line) between Sangkhla Buri and Samut Prakan is approximately 179 miles respectively 289 kilometers.
By car or train, the actual journey to Samut Prakan is certainly longer, as only the direct route (as the crow flies) between Sangkhla Buri and Samut Prakan has been calculated here.
Air line (approximately)
289 kilometers
156 nautical miles