The calculated distance (air line) between Badalona and Sant Boi de Llobregat is approximately 13 miles respectively 21 kilometers.
By car or train, the actual journey to Sant Boi de Llobregat is certainly longer, as only the direct route (as the crow flies) between Badalona and Sant Boi de Llobregat has been calculated here.
Air line (approximately)
21 kilometers
11 nautical miles