The calculated distance (air line) between Nakhon Pathom and Samut Sakhon is approximately 24 miles respectively 39 kilometers.
By car or train, the actual journey to Samut Sakhon is certainly longer, as only the direct route (as the crow flies) between Nakhon Pathom and Samut Sakhon has been calculated here.
Air line (approximately)
39 kilometers
21 nautical miles