The calculated distance (air line) between Dan Khun Thot and Samut Prakan is approximately 136 miles respectively 219 kilometers.
By car or train, the actual journey to Samut Prakan is certainly longer, as only the direct route (as the crow flies) between Dan Khun Thot and Samut Prakan has been calculated here.
Air line (approximately)
219 kilometers
118 nautical miles