London has four main airports: Heathrow, Gatwick, Luton and Stansted. There are frequent public transport services between all four airports and to the city centre. The services run frequently, apart from transfers between Stansted & Luton airports. Allow 1-2 hours for inter-airport transport.

Most international travellers arrive at London's busy Heathrow Airport, located 24km west of the city centre. Heathrow Airport consists of 4 terminals. Terminals 1 to 3 are in the middle of the airport surrounded by the runways. Terminal 4, (dominated by British Airways) is on the south boundary of the airport. You can use the Heathrow Express train to travel for free between Terminal 4 and the central area; train runs every 15 minutes.

There is a multitude of transport options between Heathrow and London centre.

Bus
National Express Coaches run several coaches an hour from the central bus station at Heathrow to Victoria Coach Station in central London. These are reliable, comfortable coaches most of which have onboard toilets. Journey time is around an hour and is dependent on traffic conditions. 

Shuttle Bus
A frequent door to door shuttle bus is available to transport all travellers to any Central London hotel. This is a shared service using mini buses carrying around 8-10 people. 
Journey time depends on whether you are first or last off the bus. If you are travelling with two or more people, it’s cheaper to get a taxi.

Taxi
The black London taxis that queue outside each terminal are well-regulated and boarding is very orderly.  Fares are complicated but should be around £40-£50, depending on destination, time of day and traffic conditions.

Train
The Heathrow Express runs every 15 minutes into London. This is the fastest and most expensive option (15 minutes to Paddington Station). A cheaper train alternative called the Heathrow Connect also runs along the same track but doesn't service Terminal 4. If you are travelling with two or more people, it’s cheaper to get a taxi.

Underground (Tube)
The London Underground network is by far the cheapest option, taking around 45 minutes to reach the city centre from Heathrow Airport. The placement of Underground stations is frequent, so there will most likely be an underground station very near your central London destination. Downside is chronic crowding of the carriages which can be stressful and uncomfortable if you have lots of luggage after a long flight.

Gatwick Airport is around 48km from Central London. Flights are a mix of standard international, low cost budget airlines, and charter flights.

Bus
National Express Coaches provide the cheapest link between Gatwick and Central London at the expense of speed. Unlike the train options they have to contend with London's traffic, therefore are a slower option. Hotelink run a service whereby they meet you off the Gatwick Express train and then transport you by minibus to your Central London accommodation.

Train
The Gatwick Express is the fastest and most comfortable option (30 minutes to Victoria Station). The terminus in Central London is also very central and a good transit point to your accommodation.

The Thameslink Train runs a different route into Central London and stops at several stations except for Kings Cross. It is just as fast and is significantly cheaper than the Gatwick Express.

The local trains run the same route as the Gatwick Express. They take about 15 minutes more to Victoria than Gatwick Express. Local trains can get very crowded at peak times, but are a much cheaper option than the Gatwick Express. There are also direct services to the Kensington district and they can be used to make a reliable transfer to Waterloo station for Eurostar services.

Luton Airport is situated 56km north of London and is the smallest of the four airports. Luton is dominated by low cost budget airlines Ryan Air and EasyJet. Since the terminal is relatively small, quick baggage claim and short walks are the norm. Despite its size, Luton Airport offers a choice of food outlets, foreign exchange and all the basics you need at an airport.

Train
Thameslink is the fastest and most expensive transfer option between Luton and London. 

At the time of writing, Luton has no train station. To get to the Luton Airport train you have to take a frequent free shuttle bus between Luton Airport and Luton Parkway station. 

The journey takes only five minutes and buses pull up outside the front door of the passenger terminal. Trains run up to eight times in an hour. The journey takes around 30 minutes. 

Bus & Minibus
Two bus lines transport passengers into London. Green Line is the major operator running full size coaches into London, terminating at Victoria station and dropping off at many points in between. The Green Line picks up directly in front of the terminal at Luton in the coach/bus station. EasyBus operates a minibus fleet non-stop to Baker Street. Travel time depends on traffic (1-2 hours).

Stansted Airport is situated 60km north of London, and is the city’s fastest growing airport, most of the growth coming from low cost budget airlines. Stansted flights are almost exclusively European and domestic UK.

There is a railway station below the single passenger terminal and a large bus terminal next to that.

Bus
National Express A9 Stratford bus runs non-stop to the nearest Underground station from Stansted at Stratford station in east London.

National Express A6 Victoria runs through central London. It stops at many Underground stations in the centre before terminating at Victoria station.

Terravision Victoria Bus runs a competing service against National Express, but without any stops from Standsted to Victoria station. Terravision Liverpool Street Bus transports passengers to Liverpool street.

Train
Stansted Express trains are a fast, comfortable but expensive option, complemented by four competing airport bus routes meeting the needs of budget travellers. Stansted Express takes 45 minutes to reach Liverpool Street Station.

Bus
National Express operate a network of coach routes out of Victoria Coach Station offering daily services to/from most towns and cities in the UK. Frequency is high on the main routes. Eurolines offer daily services to/from Ireland and continental Europe.

The Eurostar train service links London with Paris and Brussels to/from London's Waterloo Station. The train service takes just a couple of hours or so to both to Paris and Brussels, so with an early start it is possible to enjoy a day trip to Paris. Like all train fares in the UK the fare structure is highly complex. To get the best fares you have to book at least 2 weeks in advance. www.eurostar.com/

Train
If you are travelling into London by train combine your ticket with a London Travelcard ticket (see below: Getting Around London). If you book a ticket through The Trainline to London, a Travelcard extension to your ticket is normally offered as an option.

Car Hire in London and all airports is available though getting around London can be challenging if you're not used to busy inner city driving. For excursions outward into the suburbs and countryside, it can be quite enjoyable to have your own auto, making side trips easy. Remember that they drive on the left side of the road and be sure to bring your passport together with a valid international driving licence.

The London Travelcard is for most the ideal solution to their public transport needs. The Travelcard allows unlimited travel on the Underground, buses, and trains in the London urban area. You also get a discount on many of London's scheduled river services.

Travelcards can be purchased from Underground stations and tourist information centres. There are also countless other ticketing outlets with a prominent sign in their window.

Travelcards are good for 1, 3 or 7 days (there are also monthly and yearly passes). London public transport is divided up into six circular zones radiating out from the centre. The more you pay, the more zones you need. Most visitors will only need Zones 1 and 2 where all the major attractions are located. Heathrow Airport is in Zone 6.

Bus
London's famous red buses are very frequent and cheap for those willing to decipher the route map. Most buses run from around 5 am to midnight. At other times there is a night bus service on many routes.

River Boat
Lightly used by locals, there is a small network of scheduled river services along the Thames. River boats serve as memorable transport to Tower of London, Greenwich and Hampton Court. Travelcards get half price fares. 

Train
London has many stations forming a circle around inner London. There is a comprehensive commuter service that will get you quickly to sights like Windsor, Hampton Court and Greenwich as well as services throughout the UK and beyond.

For most visitors the Underground will serve as their transport of choice. Many London tourists rate the Underground as a highlight of their visit. There is invariably an Underground station nearby where you want to go, and finding yourself around the system is very easy. The fare is dependent on how many zones you travel across.