We have found out that the metro in Barcelona operates from 05:00 to midnight (most of the time). However we have planned a couple of trips which last longer than that. Any idea if the buses operate past midnight, or even 24hr?
Like many other cities, the metros and regular buses stop at night (between midnight and 5am most nights). There is a different night bus network (NitBus) in Barcelona and its suburbs with 18 lines (N0 to N17). I believe that the fares and passes are the same as for the day buses.