The line is owned and operated by BC Rapid Transit Company, a subsidiary of TransLink, and links the cities of Vancouver, Burnaby, Coquitlam and Port Moody.

The line is elevated to Burquitlam station, where it then goes through a 2-kilometre (1.2 mi) bored tunnel to the city of Port Moody.

[7] An 18-month review of rapid transit was scheduled and started in January 1998 but was cut short by the government's announcement of its choice of Bombardier's technology in June 1998.

The main contractor for the project was SAR Transit, a joint venture of SC Infrastructure, Agra Monenco, and Rizzani de Eccher Inc.[9] The Millennium Line opened for revenue service on January 7, 2002 (a preview for SkyTrain passengers took place on the prior two days),[10] with trains operating between Waterfront station on the Expo Line and Braid station in eastern New Westminster.

A short spur[19] and switches to the PMC Line were installed to the east of Lougheed Town Centre station and a third platform was roughed-in in anticipation of the extension.

At one point prior to 2008, the mode planned for the extension was changed to light rail instead of SkyTrain, which meant that the junction tracks would have remained unused.

As a result, the junction tracks and roughed-in third platform at Lougheed Town Centre station were used as part of the Evergreen Extension.

[21][22] On March 16, 2018, the provincial government approved the construction of the "Broadway Subway Project", an initiative which will extend the Millennium Line west to Arbutus Street and add six new stations.

[27] While six new stations are confirmed for the Broadway extension, one will become part of the existing Broadway–City Hall Canada Line station, which is scheduled to be upgraded as part of the project:[b][28][29] Preliminary work on the extension began on February 19, 2019, with the installation of trolley poles and wires on 12th Avenue between Arbutus and Granville Streets that were required in order to reroute trolley buses off of Broadway for the duration of the construction of the subway.

[32] The provincial government initially had a plan to have a contractor selected by April 2020 to allow for construction to begin later that year.

[33] On July 17, 2020, the provincial Ministry of Transportation announced that Acciona Infrastructure, a Spanish conglomerate, and Ghella, an Italian company, would be in charge of construction.

[34] Demolition of buildings, to make room for station entrances and construction staging areas, began in February 2021.

This 700-metre-long (2,300 ft) guideway is the only above-ground portion of the extension and connects the existing VCC–Clark station to a tunnel portal adjacent to the Emily Carr University of Art and Design.

On February 15, 2019, the TransLink Mayors' Council again approved an extension of the line to the UBC campus, although funding for this continuation past Arbutus Street had not yet been secured.

[45] In 2022, TransLink unveiled a proposed route for the extension: the line would continue west under Broadway, with stations at Macdonald and Alma Streets.