Part of the line is still under construction, with 17 stations currently in operation in Barcelona, Badalona and L'Hospitalet de Llobregat.

[1] The line will link the Zona Franca with Badalona, through Barcelona proper, sharing most of the area covered by L9.

Originally expected to be ready by 2008, ongoing problems with its construction are going to delay its completion until as late as 2025.

Provençana station opened to the public on 2 March 2019 followed by Ciutat de la Justícia on 24 November 2019.

On 7 November 2021, the section from Zona Franca to ZAL - Riu Vell opened to the public.