The calculated distance (air line) between Terrassa and Sant Boi de Llobregat is approximately 15 miles respectively 25 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 Terrassa and Sant Boi de Llobregat has been calculated here.
Air line (approximately)
25 kilometers
13 nautical miles