Barcelona airport is located about 15 kilometers outside the city. It was formerly called "Barcelona El Prat de Llobregat" a quite leisurely airport with short distances; it has now become more than twice as large with the T1 terminal, which opened in 2009. The old A, B and C terminals are now T2-A, T2-B and T2-C. Free shuttle buses run between the T1, T2 and the train station every 5 minutes. Despite its size, it is still easy to find your way around.
From here there are several ways to get into the inner city:
The Aerobús is a shuttle bus that takes you directly to the city centre. On the bus there is plenty of storage space for luggage, you do not need a timetable, the buses run in a tight cycle every 5-20 minutes. The Aerobús runs 365 days a year from the airport to the city centre from 6:00 to 1:00, and in the opposite direction from 5.30 to 0.30. The ticket costs just € 5.65, € 9.75 round trip (valid for nine days), you can get it from the machine before the bus stops, at a busy bus stop in front of the cashier or directly from the driver. For the drivers, however, no card payment is possible.
Since the Aerobús is operated privately, the Barcelona Card is not valid here. The trip to the city centre takes about 35 minutes.
Upon arrival, both A1 and A2 bus lines drive to Plaça Espanya, then to the Gran Via-Urgell, Plaça Universitat stations and Plaça Catalunya, the last stop. On the return trip be sure to get on the right bus (A1 for terminal T1 and A2 for terminal T2) and please note that because the bus does not stop at Plaça Universitat, you will have to get on at Plaça Catalunya.
Here you can find more information on Aerobús.
The urban bus routes 46 and N17 are the cheapest way to get into the city. It’s even free if you have the Barcelona Card. They are not so comfortable - there are no luggage racks and the bus stops at many stops to take on more passengers.
The Barcelona Card gives you free travel on the airport train and the 46 and N17 buses.
You can get single tickets, if necessary, from the driver, but no multiple or multi-day tickets are available. The bus line 46 ends at Plaça Espanya and the N17 ends at Plaça Catalunya.
The bus line 46 is in operation from the airport from 5.30 till 0.45, and in the opposite direction from 5.00 till 0.15. The line N17 is in operation from 23:00 till 5:00. The journey takes about 40-60 minutes depending on time of day, the buses run every 25 minutes. You should allow sufficient time for the return trip to the airport.
The 46 and the N17 bus lines from the airport stop at Plaça Espanya onthe side of the exhibition centre - the 46 has its terminus there. The entrance to the Espanya Metro station (lines L1, L3 and L5 as well as several other trains) is about 100 meters from the tram stop, near the two Venetian towers. The N17 has its terminus at Plaça Catalunya. The Bus 46 to the airport leaves from Plaça Espanya at the "Las Arenas" shopping center.
The airport train station is located opposite the T2-A / B Terminal. A pedestrian bridge from the terminal building to the station facilitates transfer, especially with lots of luggage. If you are traveling through Terminal T1, you can take the free shuttle bus from T1 to the station at T2. You can reach the bus stop for the shuttle bus when you leave the security area and going straight ahead (going around the café). After about 50 metres you come to the exit for the train station. Follow the signs (signs and lines on the floor). The shuttle buses run every 5 minutes between the terminals, and using these buses is free.
Trains run every 30 minutes between the airport and the city centre. From the airport the single line of the R2 North line runs to the main Sants Estació station. The ride from the airport to Sants Estació takes 17 minutes.
From the station you have access to the Metro network in Barcelona (lines L3 and L5). From here you can get without transfer directly to the old town and Plaça Catalunya with the L3 Metro, and to the Eixample district with the L5.
If you have you booked the Barcelona Card, then usage of the train from the airport to the city centre and within the city of Barcelona is included in the price, as well as the use of the Metro and other public transportation.
Taking a taxi is the easiest way to get to your hotel. At the T1 Terminal go to the taxi rank when you come out of the security area; about 30 meters straight ahead and then go down to the exit. The ranks are well signposted. At the T2 Terminal the taxi rank is located right outside the terminal building.
For the taxi, you should expect to pay €30-60, depending on luggage, time and route chosen, including surcharges for the airport. The availability of taxis is very good, but you can expect to wait at the queue. Do not expect that the taxi drivers speak English or even German. Check if the driver has turned the meter on, you are only obliged to pay the amount indicated.
Something more comfortable with a private arrival transfer? The driver will pick you up in the arrivals hall, take care of your luggage. The Private Transfer is available at a fixed price.

The Barcelona Card provides free travel by bus, tram, metro and train from the airport to the city centre and back. Many other discounts.

In T1, the Tourist Information Office, where you can pick up your pre-booked Barcelona Card or tickets for the Hop-on Hop-off bus, is located about 50 metres to the right after the exiting the security area

In the T2 Terminal the Tourist Information Office is located directly beside the exit to the street, in the arrivals hall close to the exit from the security area.

Access to bus stops in T1 Terminal, about 50 metres straight ahead after exiting the security area.

Bus stop for Bus 46 at the T1 Terminal.

Bus stop for Bus 46 at the T2B Terminal, on the right about 100 metres away from the exit.

Access to the train station at Barcelona airport.

A Private Taxi Transfer makes arrival and departure very easy.