Waterloo tube station is a London Underground station located within the Waterloo station complex that incorporates both the tube station and the mainline railway station. It is the busiest station on the Underground network with over 89 million passenger entries and exits in 2013, and it is served by four lines: the Bakerloo, Jubilee, Northern and Waterloo & City lines.
The station is situated in fare zone 1 and is located near the South Bank of the River Thames, in the London Borough of Lambeth.
The first Underground station at Waterloo was opened on 8 August 1898 by the Waterloo & City Railway (W&CR), a subsidiary of the owners of the main line station, the London and South Western Railway (L&SWR). The W&CR, nicknamed "The Drain", achieved in a limited way the L&SWR's original plan of taking its tracks the short distance north-east into the City of London.
On 10 March 1906, the Baker Street & Waterloo Railway (BS&WR, now the Bakerloo line) was opened. On 13 September 1926, the extension of the Hampstead & Highgate line (as the Charing Cross branch of the Northern line was then known) was opened from Embankment to the existing City & South London Railway station Kennington with a new station at Waterloo.
As a subsidiary of the L&SWR and its successor, the Southern Railway, the W&CR was not a part of the London Underground system. Following nationalisation of the main line railway companies in 1948, it became part of British Railways (later British Rail). Following a period of closure during 1993 when the line was converted to use the four rail electrical system of the London Underground, the ownership of the Waterloo & City line was transferred to the Underground on 1 April 1994. Due to an Easter shut-down, the first Underground service on the line was on 5 April 1994.
On 24 September 1999, the Jubilee line station was opened as part of the Jubilee Line Extension. The station was temporarily the western terminus of the extension running from Stratford in east London, before the final section to link the extension to the original line was opened between Waterloo and Green Park on 20 November 1999. The Jubilee line platforms are at the opposite end of the site from those of the Bakerloo and Northern lines, but the two ends are connected by a 140-metre (460 ft) moving walkway link (one of only two on the Underground; the other gives access to the Waterloo & City line platform at Bank station).
Today the station is served by London Buses routes 1, 4, 26, 59, 68, 76, 77, 139, 168, 171, 172, 176, 188, 211, 243, 341, 381, 507, 521, RV1, X68 and night bus routes N1, N68, N76, N171, N343 and N381.