Owned by Euskal Trenbide Sarea, it runs from Lezama to Matiko, from where it continues as line 3 of the Bilbao metro.

In February 1891, the government granted Juan de Urrutia y Burriel the concession for a railway between Bilbao and Lezama, for which proposals had been made since 1886.

[1] In order to cross Mount Artxanda, a short 445 m (1,460 ft) tunnel was built, which required a sinuous and steep alignment on both sides of the mountain.

Two days after the completion of the Artxanda tunnel, the Bilbao City Council opened a competition for a new municipal cemetery.

The backers of the railway bought a plot of land near Derio and handed it over for free to the city council, in order to create a source of traffic for the line.

The Bilbao–Lezama Railway Company (Spanish: Compañía del Ferrocarril de Bilbao a Lezama) was founded in May 1893.

[2] The line opened partially between Begoña and Lezama (currently known as Kurtzea) on 2 May 1894 due to delays in the construction of a tunnel and the Bilbao-Calzadas terminus.

[3] Two months after the opening of the line, on 7 July, a train descending from Artxanda towards Begoña derailed, killing 13 people.

[6] However, instead of closing the line, the company decided to build a new alignment from Bilbao to Derio through Mount Artxanda which would shorten travel times and improve the overall service.

FTS ceased operations in 1977, and its services were provisionally taken over by FEVE before being transferred to Basque Railways in 1982.

[22] The extension to the airport would branch off the Txorierri line east of the new Sondika station, reaching the terminal through a 2.5 km (1.6 mi) tunnel under the runways.