The calculated distance (air line) between Samut Prakan and Hua Hin is approximately 83 miles respectively 134 kilometers.
By car or train, the actual journey to Hua Hin is certainly longer, as only the direct route (as the crow flies) between Samut Prakan and Hua Hin has been calculated here.
Air line (approximately)
134 kilometers
72 nautical miles