Southampton Citybus was formed in 1898 as Southampton Corporation Transport when the town council took over the Southampton Tramways Company. The company initially operated a fleet of horse-drawn trams and buses, replacing them with electric trams in 1901. A motorbus service was launched in 1901 but proved unsuccessful, and was withdrawn until 1919, when it was reintroduced. The tram network was expanded during the 1920s, but by 1929 it was decided that no new tram services would be introduced. A ferry operation across the River Itchen was acquired in 1934, and operated until 1977 when a bridge was opened in its place. Tram services began to be closed in the 1940s, with the last operation abandoned in 1950. The bus network continued largely unchanged until 1986, when the company was reformed as an arms length operation and renamed Southampton Citybus. Southampton Citybus was owned by the city council until 1993. It operated a fleet of around 150 vehicles, and a small coaching division named Red Ensign. Following the Transport Act 1985 and the deregulation of the bus market, it faced aggressive competition from Southern Vectis, the dominant Isle of Wightbus company, which started Solent Blue Line in 1987 as a bid to expand onto the mainland, competing on some of the same major routes as Citybus. In response Citybus introduced crewed AEC Routemasters.
Privatisation
The council sold the company to its employees in 1993 for around £3 million. Following this Citybus introduced sixteen natural gas powered Dennis Dart buses into regular service, the largest such fleet in the UK. Much of the fleet of 160 buses was replaced during this period, and the company was profitable.
Purchase by First
On 28 July 1997 the company was purchased by FirstGroup for around £11 million. After a brief period where the name was kept, the service became First Southampton, and later part of First Hampshire & Dorset. In 2014, First Hampshire & Dorset introduced a new brand for high-frequency routes in Southampton, City Red, with a red variant of the First livery, marking a return of the traditional Southampton colour. Some of these buses carry the slogan "Southampton's city buses". Some ex-Southampton buses are looked after by .