Connecting at London Heathrow: how much time you need

Heathrow doesn't publish a minimum connection time. Its answer is that there's no single number: it depends on your route, your airline, whether you have to collect bags and whether you change terminal, and your airline can confirm it.

What that means in practice depends on how you booked:

• One ticket: your airline quotes a minimum connection time, and airlines only sell connections that meet the airport's minimum requirements. If your first flight is late and you miss the second, speak to your airline about rebooking.
• Separate bookings: those minimums don't apply. The airport advises allowing plenty of extra time, for example to collect bags and go through passport control.

See what happens if you miss a connection for your rights under UK and EU rules.

Terminals and how to get between them

Heathrow has four terminals: 2, 3, 4 and 5. Your connecting flight may leave from a different terminal from the one you arrive at.

• Follow the purple signs. They guide you through the connection.
• Same terminal: walk, or take the free tram.
• Different terminal: take the free shuttle bus, which runs every 10 minutes.
• Gate numbers only appear on the departure boards after you've been through security.

Security for everyone, immigration for some

• Every connecting passenger goes through security again at Heathrow, because every flight leaving a UK airport follows UK security rules. When you connect, large electrical items and liquids up to 2 litres can stay in your cabin bag.
• Immigration: you don't go through it unless you arrive on an international flight and connect to a flight within the UK or to the Republic of Ireland. On those connections, a biometric image of your face is taken before security.

UK entry permission for transit

• If your connection means passing through UK border control, for example on separate tickets where you collect bags, you need an electronic travel authorisation (ETA) unless you're exempt.
• If you stay airside and don't pass border control, some nationalities still need a Direct Airside Transit visa. Check the UK government's transit visa page for your nationality.

The EU's Entry/Exit System doesn't apply in the UK.

Keep an eye on the first flight

Before you travel, add both flights to FlyingOver while you're online. You can then follow the first flight offline and see its estimated arrival, so you know early whether your connection is getting tight. Once you're back online, times update with live data.