Most of the major cities have excellent local transport. Madrid and Barcelona have extensive bus and metro systems, and other major cities also benefit from generally efficient public transport. By European standards, prices are relatively cheap.
Cities and provincial capitals all have reasonable bus networks. You can buy single tickets (usually between €1 and €2) on the buses or at estancos (tobacconists), but in cities such as Madrid and Barcelona, you are better off buying combined 10-trip tickets that allow the use of a combination of bus and metro, and which work out cheaper per ride. These can be purchased in any metro station and from some tobacconists and newspaper kiosks.
Regular buses run from about 6am to shortly before midnight and even as late as 2am. In the big cities, a night bus service generally kicks in on a limited number of lines in the wee hours. In Madrid they are known as búhos (owls) and in Barcelona more prosaically as nitbusos (night buses).
Madrid has the country’s most extensive metro network. Barcelona has a reasonable system. Valencia, Zaragoza, Bilbao and Seville have limited but nonetheless useful metro (or light rail) systems.
You can find taxi ranks at train and bus stations, or you can telephone for radio taxis. In larger cities, taxi ranks are also scattered about the centre, and taxis will stop if you hail them in the street – look for the green light and/or the libre sign on the passenger side of the windscreen. The bigger cities are well populated with taxis, although you might have to wait a bit longer on a Friday or Saturday night. No more than four people are allowed in a taxi.
As elsewhere in Europe, Uber's presence in Spain has been controversial, leading to taxi strikes and court orders banning the company. At the time of writing, Uber operates services (either as Uber or UberX) in Madrid and Barcelona.
Trams were stripped out of Spanish cities decades ago, but they’re making a minor comeback in some. Barcelona has a couple of new suburban tram services in addition to its tourist Tramvia Blau run to Tibidabo. Valencia has some useful trams to the beach, while various limited lines also run in Seville, Bilbao, Murcia and, most recently, Zaragoza.
Spain’s network of train and bus services is one of the best in Europe and there aren’t many places that can’t be reached using one or the other. The tentacles of Spain’s high-speed train network are expanding rapidly, while domestic air services are plentiful over longer distances and on routes that are more complicated by land.