The London public transport system is for the leisure visitor, one of its great assets and opportunities. An organisation called Transport for London coordinates the various transport options on offer; namely buses, underground railway, overground railway, Docklands light railway, and river transport. This network covers the whole Greater London area with a comprehensive network of services. The only airports within this area are Heathrow and London City Airports.

The area is organised in six circular zones which ripple out from the centre. Nearly all the places visitors want to travel to and nearly all hotel accommodation is in Zones 1 and 2, though Heathrow is in Zone 6.
For the sake of simplicity we will focus on this inner area, zones 1 and 2.
Public transport here is dominated by the London Underground and London's famous red buses.

You cannot board any bus or train without pre-purchasing a ticket. The single fare on a bus is a flat fare however far you travel. The London Underground fare is determined by the number of zones you travel through on a journey. You can switch trains between the various lines within any single journey.

At Underground stations there is always a manned ticket office and automatic ticket machines. At bus stops there is a ticket machine where you can purchase bus tickets.

All underground lines and bus routes operate between about 05:00 and 24:00.
There is also a worthwhile network of night buses, especially in the centre of London which for the night owl are both frequent and comprehensive enough to be of real value.

Nearly all travellers on London's public transport system do not pay for individual journeys though. Instead one of the multi-trip passes is used. The fares set by Transport for London make it much cheaper to purchase one of these cards than to pay individually for each journey.
For the visitor the easiest place to purchase any of the passes is a London Underground ticket office or a local retail ticket point. You will see signs in the windows of many shops, especially newsagents, advertising that they sell the range of ticketing options at the same price as from the Underground Stations.

The most popular option for the visitor to London is the one day or three day Travelcard. This covers all public transport options within set zones. The Heathrow Express train is not covered by the pass. For the vast majority of visitors to London this means a Zone 1 & 2 Travelcard.
During weekdays there are two fare options, you have to pay significantly more if your Travelcard is used before 09:30 during the week.
Children, (less than 16 years old) travel free on the buses. You can also purchase a Travelcard for children for just 1 pound sterling covering all zones.
If you purchase a Travelcard for just zones 1 & 2, you can use it for the buses on all zones.

On buses you just show your card to the driver as you board. If you board one of London's long single deck 'bendy' buses get on through any entrance and be prepared to show your ticket for inspection. Hit squads of inspectors descend on a bus sealing all exits and will demand a valid ticket to be shown.
On the Underground you will have to insert your ticket into a barrier on entering and exiting stations to gain entry and exit.

You will also see many references to the 'Oyster Card' scheme. These are really aimed at residents of London. You will see yellow pads on buses and at the ticket barriers at Underground Stations. Oyster Cards are credit card sized cards that can be electronically loaded with electronic money or a season ticket. For example you can load say 10 GBP onto your card, when you swipe that card to gain access to a bus the fare is automatically deducted from the 10 GBP value on your card.

The big attraction is the sizable discounts on individual journeys purchased this way. Most Londoners will have season tickets which are also held in the Oyster Card. The product most attractive to visitors is the 7 day Travelcard. You cannot purchase a 7 day Travelcard without having an Oyster Card.

The feature of Oyster Cards which discourages most visitors, especially overseas visitors, is the fact you have to pay a 3 GBP refundable deposit for an Oyster Card. When you no longer require the Oyster Card you hand it in and fill in a form. You do not receive any money there and then, instead a sterling cheque is sent to your home address at a later date.