Barcelona is a huge city, but the modern and very extensive public transport system gets you almost anywhere. The metro, buses and trains are all part of the same Barcelona public transport system TMB (Transports Metropolitans de Barcelona), allowing tickets to be valid in all the different means of public transport, with the exclusion of the Aerobus (the express bus service to the airport) and the double-decked sightseeing buses.
This Integrated (TMB) Fare System means that you can use metro, urban, metropolitan and interurban buses, tram, Ferrocarrils de la Generalitat de Catalunya trains and Rodalies de Catalunya trains for a specific time period, depending on the number of zones for which the travel card is valid. You are allowed to make three changes, from metro to bus, from bus to tram and vice versa, within the designated zones.
What they don’t tell you is that a single ticket is not part of the integrated fare system; therefore, it is only valid for a single journey with the transport operator from which you bought it. Another note of caution: the total ride duration of a single journey should not exceed 75 minutes. You can buy tickets at any metro station and TMB station using the multi-language vending machines or the pay booths. A single ticket will set you back €2.00 per ticket.
If you are in Barcelona for more than one day it makes more economical sense to buy the T10 (10-journey) ticket. A T10 ticket will entitle you to 10 journeys on the metro, FGC (FGC run train lines) buses, tram and RENFE, all in zone 1 (the main city centre areas are all in Zone 1).
If you prefer an unlimited number of journeys for the duration of your stay take a Transport Card ( 2-, 3-, 4-, or 5-day Barcelona Transport Card) or the travel & discount card called the Barcelona Card, featuring free travel on public transport, discounts and free offers at museums, cultural venues, leisure facilities, night-clubs, shops, restaurants etc.
And oh, let’s not forget the other means of transport, some with a special charm of their own: the funicular (Funicular de Montjuïc, Funicular del Tibidabo), the Telefèric Montjuïc, Tramvia Blau, taxis and Barcelona cycling.