Barcelona Airport Transport: RENFE Train

The community train line is another option to travel from and to the Barcelona Airpot. It is fast, numerous stops are available on the RENFE line and it is cheaper than the Airbus Shuttle.
There is a very detailed information about the stops on the route and the schedule of the trains at the RENFE official web-site:
RENFE Barcelona

If there is no direct stop on the location you need to go to, you can easily transfer on some of the Metro lines and get there easy and fast.

Price: 3.60 EUR

Can be used for free with the Barcelona Card

Barcelona Airport Transport: NitBus N17

The NitBus N17 travels at night and it leaves from the Plaça Catalunya, stopping on multiple statios to its' way to the Airport. This is a convenient and cheap way to travel from adn to the airport at night.
The bus stop on the Plaça Catalunya square is located near the Ronda University and if you are boarding from some of the otehr stops of the line, it is very important to know the exact name of the bus stop.
The line is part of the municipal transport and you can use the standart multitrip transport cards.

Price:
single trip: 2.00 EUR

Detailed information and list of the bus stops:
http://www.emt-amb.com/principales/TiraLinea.aspx?linea=224

Can be used for free with the Barcelona Card