The networks, except the Olympic Park and On Demand routes, are part of Transport for NSW's Opal ticketing system.

In the 2019-20 financial year, 229.5 million passenger journeys were made on services in Sydney's bus contract regions.

[2] The city's second bus route ran from Newport, in the north of the Northern Beaches district, to Manly, commencing in 1906.

[3] The return of servicemen from World War I in the late 1910s provided fresh impetus to the motor omnibus industry.

[5] The Department introduced its first bus service, route 144 from St Leonards to Manly, on Christmas Day of that year.

On the one hand, the Department – forerunner to today's State Transit Authority – began to shut down its trams and build an extensive bus network serving the inner suburbs and Northern Beaches.

On the other, the heavily regulated private operators remained small-scale, relegated to the status of feeder services for the Government's trains.

But the Department's focus began to shift inexorably towards building its bus network, starting in 1937 when Kogarah's steam trams were replaced with trolleybuses.

[2][6] For much of the 20th century, land use planning in Sydney restricted development to corridors within a short distance of the existing railway lines.

This discipline broke down in the 1980s, however, when the Wran Government released new areas for development far from existing rail lines.

[7][8] This meant that buses outside of the inner-city, government-operated network, would play an increasing role in meeting Sydney's transport needs.

Although the government was loath to challenge the operators' local dominance, it insisted on forming contractual relationships between bus companies and the Department of Transport.

These formed the basis for improvements to service standards and – in time – would allow the Government to consolidate the industry and create a truly integrated public transport network.

The Government also dismantled one of the shibboleths of the Lang era, allowing Forest Coach Lines and Westbus to run direct services to the City, rather than just the nearest train station.

Development in the Hills and Forest districts, far from railway lines, meant that long-distance private bus services poured across the Harbour Bridge to the City each morning.

The growth of employment centres outside of the City and inner suburbs, including the growing significance of Parramatta, meant that more and more commuters were making cross-regional, rather than suburb-to-city, trips.

In return for their acceptance of limits to their operations, the small family-owned bus companies had enjoyed immunity from competition themselves.

[23] This is a bus rapid transit route operating in the south western part of Sydney, mostly along dedicated bus-only roads.

The original Metrobus routes run along major inner city corridors, passing through the Sydney central business district without terminating there.

[34][35] In April 2024, it was announced by the state government that the metro conversion was expected to begin between July and October 2024 and operate for up to 12 months.

[37] Buses are also frequently used to replace train lines that are closed for trackwork, mainly on weekends or late nights.

Major events that affected the number of journeys made or how patronage is measured are included as notes.

These are Asia Motors, Bustech, Custom Coaches, Heavy Vehicles Australia, Hino, Iveco, MAN, Scania, Volgren and Volvo.

Opal is also valid on metro, train, ferry and light rail services but separate fares apply for these modes.

[64] The following table lists Opal fares for reusable smartcards and single trip tickets:[65] ^ = $2.50 for Senior/Pensioner cardholders