The calculated distance (air line) between Sant Boi de Llobregat and Martorell is approximately 11 miles respectively 17 kilometers.
By car or train, the actual journey to Martorell is certainly longer, as only the direct route (as the crow flies) between Sant Boi de Llobregat and Martorell has been calculated here.
Air line (approximately)
17 kilometers
9 nautical miles