Barcelona’s airport, Barcelona-El Prat Airport, is roughly 15km/10 miles from the city centre and the cruise port. The simplest and quickest way to travel between the two is to pick up a taxi outside the airport - the journey will take around half an hour and fares are fixed.
Alternatively, you could choose the public metro and bus service. Take the metro Line 9 at the airport, and transfer to Line 3 at Zona Universitaria. Then get off at Drassanes station, at the end of La Rambla.
From here, it's a five minute walk to the cruise shuttle bus stop. At the bottom of La Rambla, turn right at the Monument a Colom roundabout, taking the second exit on to Passeig Josep Carner. After 200 metres, you will reach the roundabout at Plaça de Les Drassanes. Turn left here, heading for the twin roads. lined with trees, which lead to the World Trade Centre. You'll find the cruise bus stops along these roads. Look for a bus named T3/PortBus or Cruise Bus, which comes every 15 minutes or so. One way or return tickets cost a few Euros.
By bus, take the A1 from the airport to Plaça d'Espanya, then walk about 200 metres to Avenida del Para-lel (the second exit from the roundabout). From the Pl Espanya - Paral·lel bus stop, take the D20 to Les Drassanes. When you get off the bus, you'll be on Passeig Josep Carner - follow the directions above to reach the cruise bus stop.
For more information, see our Barcelona airport guide or www.tmb.cat.