London's public transport system serving both central London and the wider Greater London area, is organized into nine zones, numbered 1 through 9.
The central area, where most major attractions are located, is within zones 1 and 2. Zones 1 to 4 across almost the entirety of London, including Heathrow and London City airports.
For a complete view of the Transport for London (TfL) Tube, Overground and Elizabeth Line network, click here.