The calculated distance (air line) between Vilanova i la Geltrú and Castelldefels is approximately 13 miles respectively 21 kilometers.
By car or train, the actual journey to Castelldefels is certainly longer, as only the direct route (as the crow flies) between Vilanova i la Geltrú and Castelldefels has been calculated here.
Air line (approximately)
21 kilometers
12 nautical miles