The calculated distance (air line) between Sants-Montjuïc and La Llagosta is approximately 10 miles respectively 16 kilometers.
By car or train, the actual journey to La Llagosta is certainly longer, as only the direct route (as the crow flies) between Sants-Montjuïc and La Llagosta has been calculated here.
Air line (approximately)
16 kilometers
9 nautical miles