The calculated distance (air line) between L'Hospitalet de Llobregat and Mollet del Vallès is approximately 14 miles respectively 22 kilometers.
By car or train, the actual journey to Mollet del Vallès is certainly longer, as only the direct route (as the crow flies) between L'Hospitalet de Llobregat and Mollet del Vallès has been calculated here.
Air line (approximately)
22 kilometers
12 nautical miles