The calculated distance (air line) between Samut Prakan and Suphan Buri is approximately 68 miles respectively 110 kilometers.
By car or train, the actual journey to Suphan Buri is certainly longer, as only the direct route (as the crow flies) between Samut Prakan and Suphan Buri has been calculated here.
Air line (approximately)
110 kilometers
59 nautical miles