Metro traffic began in Helsinki in 1982 between Rautatientori (Central Railway Station) and Itäkeskus. Since then, the metro line has expanded in stages, first to Ruoholahti in 1993 and then to Vuosaari in 1998. The newest station was opened in 2007 in Kalasatama.
The extension of the metro line to Espoo has been on the table ever since the metro was introduced, and the development of the public transport system from Helsinki to the west has been studied on several occasions. The design process for the west metro was launched in March 2007 in accordance with the decisions made by the Espoo City Council and the Helsinki City Board in 2006. The construction of the west metro was approved by the Espoo City Council in its meeting on 19 May 2008 and by the Helsinki Council on 21 May 2008.
Construction begun in Ruoholahti in November 2009
The Espoo City Council decided in January 2009 to approve the metro plans. The Helsinki City Council handled the matter in November and the decision was ratified in December. Construction work begun in Lauttasaari and in Espoo in May 2010.