At the airport, both in T1 and T2 there is the metro line L9 which connects with 3 urban metro lines. One of them is the L1, another the L5 and finally the L3. You have to buy a special ticket for the airport that costs 4,50€. If you want to go to Pl. Catalunya, Ramblas, Baririo Gótico, etc... You must take either the L1 or the L3 and it takes approximately 1 hour and 10 minutes. If you want to go to the Sagrada Familia you must take the L5 and it takes approximately 1h and 15 minutes.
Travelling by taxi is one of the most comfortable ways. When you leave any of the terminals you will find taxi ranks. The official taxis of Barcelona are very easy to differentiate by their yellow and black colors. The journey to the centre takes around 30, 40 minutes and costs around 30€.
It is the bus that arrives faster to the center of the city, approximately 35 minutes it takes to arrive at Plaça de Catalunya. You will be able to differentiate it thanks to its light blue colour. The aerobus has two lines, the A1 which stops at T1 and the A2 which stops at T2. The one-way price is 5.90€ and children younger than 4 years do not pay ticket.
Access is from T2, via a covered walkway. If you are in T1 you will have to take a bus (Bustransit) to get to T2. The most central stops are Estación de Sants, Passeig de Gràcia, Clot-Aragó and Barcelona-Sant Andreu Comtal. Trains pass approximately every half hour and the price is 4,10€. The journey time to Barcelona Sants is about 20 minutes.
Rent a car
There are several companies to rent a car from the airport. Renting a car is a good option if you travel with a lot of luggage. Prices vary depending on the type of car you need. To get to the city centre you must take the C-31, which is the continuation of the Gran Via de les Corts Catalanes, the main avenue in Barcelona that crosses the city from south to north, so getting there is very easy.
The easiest and most comfortable option for the visitor to arrive in Barcelona is a private transfer service. It is obviously the least economic option but it is not much more expensive than a taxi and they wait for you with a sign inside the terminal.
These are some of the ways to get from the airport to the center of Barcelona. You can choose the one that best suits your needs.