Heathrow may operate as a single airport, but its four terminals can deliver four very different passenger experiences.

Terminals 2 and 3 sit together in the central area, while Terminals 4 and 5 occupy separate sites on opposite sides of the airport. Arriving at the wrong one is therefore more than a minor inconvenience, it can involve another train journey, a fresh walk through the airport and a potentially stressful race against the clock.

The good news is that Heathrow’s airlines are not distributed entirely at random. Terminal 2 is predominantly the home of Star Alliance, Terminal 3 accommodates a mixture of oneworld carriers, Virgin Atlantic and several independent airlines, Terminal 4 handles a broad selection of global carriers, and Terminal 5 is dominated by British Airways and Iberia.

Here is how Heathrow’s terminals work as of September 2026.

Terminal assignments can change, particularly during operational disruption or seasonal timetable changes. British Airways also operates from two terminals, so passengers should always check the terminal shown on their booking or use Heathrow’s official terminal finder before travelling.

Officially known as The Queen’s Terminal, Terminal 2 opened in its current form in 2014 and is the principal Heathrow base for Star Alliance.

The terminal is divided into the main Terminal 2A building and the satellite Terminal 2B. Short-haul flights are frequently handled from the main building, while many long-haul services use the B gates.

The walk to Terminal 2B can take approximately 15 to 20 minutes, so passengers should not assume that reaching the departure lounge means they are close to their gate.

The principal airlines operating from Terminal 2 include:

Not every Terminal 2 airline belongs to Star Alliance. Aer Lingus, Icelandair, JetBlue and Loganair are among the notable exceptions, but placing them in the same terminal can still support useful connections with partner airlines.

Terminal 2 also handles domestic and Irish services. This makes it possible to connect between Loganair, Aer Lingus and international airlines without changing terminals, provided the flights have been arranged as a recognised connection.

Terminal 3 is Heathrow’s oldest active passenger terminal and has one of the airport’s most interesting airline line-ups.

It is home to Virgin Atlantic and Delta Air Lines, several major oneworld carriers and independent airlines including Emirates. British Airways also operates a selection of routes from the terminal.

Airlines operating from Terminal 3 include:

Terminal 3 is also associated with an extensive selection of premium lounges. Virgin Atlantic operates its flagship Clubhouse here, while American Airlines, Cathay Pacific, Qantas and British Airways have lounges for eligible passengers. Independent lounge options are also available.

Most British Airways flights operate from Terminal 5, but the airline uses Terminal 3 to provide additional capacity and improve proximity to some oneworld partners.

The precise allocation of BA routes can change between timetable seasons. Passengers should therefore never assume that a British Airways flight will depart from Terminal 5 simply because that is the airline’s main home.

This is particularly important for return journeys. A passenger could depart from Terminal 5 and return to Terminal 3, leaving a parked car, hotel booking or planned meeting point at the wrong side of the airport.

Terminal 4 sits to the south of Heathrow’s runways and is physically separated from the central terminal area.

It accommodates a wide range of airlines from the Middle East, Africa, Asia and continental Europe. While several SkyTeam members use the terminal, it is no longer exclusively organised around a single alliance.

Airlines operating from Terminal 4 include:

Terminal 4 has its own Underground and Elizabeth line stations. Passengers should ensure they board a service calling at Terminal 4, as not every Heathrow train follows the same terminal pattern.

Terminal 5 is Heathrow’s largest and most recognisable terminal.

It is the principal home of British Airways and is also used by Iberia. The complex consists of three separate buildings: Terminal 5A, Terminal 5B and Terminal 5C.

Check-in, security, baggage reclaim and most public transport links are located in Terminal 5A. The B and C buildings are satellite concourses reached by an underground transit system.

The airline list is refreshingly short:

Iberia’s presence allows passengers to connect more easily between its Madrid hub and the majority of British Airways services.

However, because British Airways also uses Terminal 3, not every BA connection remains within Terminal 5.

The correct method depends on whether you are making an official airside connection or travelling landside.

If your flights form part of a single booking, follow the purple Flight Connections signs after leaving the aircraft.

Do not follow signs to baggage reclaim unless your airline has specifically told you to collect your luggage.

Heathrow provides free airside buses for passengers changing terminals. These generally operate approximately every ten minutes, although the complete transfer will take considerably longer once walking, waiting and security are included.

Every connecting passenger must pass through security again at Heathrow, even if they remain in the same terminal. Passengers arriving internationally and connecting to a domestic flight must also complete the necessary UK immigration and biometric process.

Heathrow says most checked baggage will be transferred automatically when the journey is held on one ticket, but passengers should confirm this at their original departure airport. Full guidance is available through Heathrow’s official connecting flights information.

Passengers with separate tickets are not treated as connecting passengers by Heathrow.

You will normally need to:

Terminals 2 and 3 are connected by an underground pedestrian walkway.

For journeys involving Terminal 4 or Terminal 5, rail services are generally the easiest option. Free inter-terminal rail travel is available within Heathrow, although passengers may need to touch in and out using a contactless bank card or Oyster card. No fare should be charged for a valid journey made entirely between Heathrow’s terminal stations.

Heathrow provides a terminal transfer planner showing the recommended route for each terminal combination.

The actual train or bus journey represents only one part of the transfer.

A passenger changing terminals must also walk to the transfer point, wait for the next service, travel to the new terminal, complete security and reach the departure gate.

As a practical guide:

Heathrow’s terminal system becomes considerably easier to understand once the airlines are viewed in groups.

Terminal 2 is predominantly Star Alliance, Terminal 3 is Heathrow’s mixed premium and long-haul terminal, Terminal 4 accommodates a diverse collection of international carriers, and Terminal 5 belongs almost entirely to British Airways and Iberia.

For most passengers, the biggest mistake is assuming an airline always uses the same terminal. British Airways operates from both Terminals 3 and 5, while operational changes can occasionally affect other carriers.

Always check the terminal against the operating flight number rather than relying solely on the airline named on a codeshare ticket.

Connections booked on one ticket are relatively well supported, with purple signs and airside buses guiding passengers between terminals. Self-connections require far more caution. Immigration, baggage reclaim, terminal transport, check-in deadlines and security can quickly turn an apparently generous gap into a very tight transfer.

Whichever airline you are flying, confirm the terminal before leaving home – and then check it again on the day of travel.