The calculated distance (air line) between Phnom Penh and Trà Vinh is approximately 148 miles respectively 238 kilometers.
By car or train, the actual journey to Trà Vinh is certainly longer, as only the direct route (as the crow flies) between Phnom Penh and Trà Vinh has been calculated here.
Air line (approximately)
238 kilometers
128 nautical miles