The calculated distance (air line) between Sant Just Desvern and Molins de Rei is approximately 3 miles respectively 6 kilometers.
By car or train, the actual journey to Molins de Rei is certainly longer, as only the direct route (as the crow flies) between Sant Just Desvern and Molins de Rei has been calculated here.
Air line (approximately)
6 kilometers
3 nautical miles