The calculated distance (air line) between Viana do Castelo and Vila Nova de Gaia is approximately 41 miles respectively 66 kilometers.
By car or train, the actual journey to Vila Nova de Gaia is certainly longer, as only the direct route (as the crow flies) between Viana do Castelo and Vila Nova de Gaia has been calculated here.
Air line (approximately)
66 kilometers
36 nautical miles