The calculated distance (air line) between Phan Thiết and Thốt Nốt is approximately 180 miles respectively 290 kilometers.
By car or train, the actual journey to Thốt Nốt is certainly longer, as only the direct route (as the crow flies) between Phan Thiết and Thốt Nốt has been calculated here.
Air line (approximately)
290 kilometers
157 nautical miles