The calculated distance (air line) between Uthai Thani and Samut Prakan is approximately 129 miles respectively 208 kilometers.
By car or train, the actual journey to Samut Prakan is certainly longer, as only the direct route (as the crow flies) between Uthai Thani and Samut Prakan has been calculated here.
Air line (approximately)
208 kilometers
112 nautical miles