Metro Bilbao (Spanish: Metro de Bilbao, Basque: Bilboko metroa) is a rapid transit (metro) system serving the city of Bilbao and the region of Greater Bilbao. Its lines have a "Y" shape, with two lines that transit both banks of the Nervión river and then combine to form one line that ends in the south of Bilbao. The network of Metro Bilbao is connected with Euskotren Tranbia (tram services), Bilboko Aldiriak (commuter rail services), Euskotren Trena (commuter rail services), Feve (commuter rail services, regional and long-distance trains), the Renfe service (long-distance trains) and Bilbao's bus station Termibus. It uses a meter gauge.
As of 2017, the Metro operates on 49.16 kilometers (30.55 mi) of route, with 48 stations (31 of them underground, and 17 on the surface) with 80 accesses (not counting elevators). It is the third largest Metro company in Spain by number of passengers carried (87,133,034 in 2013) behind the Madrid and Barcelona metro systems.
On February 21, 2007, the Basque Government announced a project for the construction of a third metro line, which in the future will be expanded to Bilbao Airport. Construction of the new line began in July 2008. On January 25, 2008, the preliminary layout of lines four and five was published. At the same time, the University of the Basque Country requested the construction of "Line 6" in order to connect Leioa (where the university is located) and Getxo with Asua Valley (where the airport is located) going through the university campus.
(*) The section between the stations of San Inazio and Etxebarri is the same for Lines 2 and 1 with 10.39 kilometres (6.46 mi) and twelve common stations being shared.
Besides this, most of the stations have connections with different bus lines. At the same time, Urbinaga Station was built with the intention of connecting lines C1 and C2 of Cercanías and Ansio Station with a bus terminal. However, these connection projects have not been finished as of 2011. Eventually the Urbinaga project was restarted in 2009. That future intermodal station will also take advantage of the future Leioa-Urbinaga Tram. Its construction was expected to start at the end of 2009.