The calculated distance (air line) between Prachuap Khiri Khan and Samut Prakan is approximately 134 miles respectively 216 kilometers.
By car or train, the actual journey to Samut Prakan is certainly longer, as only the direct route (as the crow flies) between Prachuap Khiri Khan and Samut Prakan has been calculated here.
Air line (approximately)
216 kilometers
117 nautical miles