Traveling from Barcelona Sants to El Prat typically involves taking the train or bus, as they're the most convenient options. From Barcelona Sants station, you can catch a Renfe train or a Rodalies Barcelona commuter train to El Prat de Llobregat station, which is near the airport. Alternatively, you can take the Aerobús, a dedicated shuttle bus service that connects Barcelona city center, including Barcelona Sants, directly to Barcelona-El Prat Airport terminals. Both options are efficient and offer frequent departures.