The Bilbao Card is public transport ticket that works with metro Bilbao, tram, Bilbobus, la Salve elevator and Artxanda´s funicular.
It is possible aldo to go on the visitis programmed by the tourist Office of the Casco viejo and the Ensanche.
With it you may have discounts in shops, restaurants and museums.
You can buy it at the departures terminal of the airport.
For more information go to the Bilbao web page here.