For a connection on a single ticket, allow at least 60 to 90 minutes if you stay in the same terminal and 90 to 120 minutes if you have to change terminals, because every departing passenger re-clears UK security and the free transfer bus adds 15 to 20 minutes. On separate tickets, allow 3 to 4 hours. Checked August 2026.
The short version
Heathrow has four terminals: T2 and T3 sit together in the Central Terminal Area, while T4 and T5 are separate satellites. How much time you need depends on three things: whether your bags are checked through, whether you change terminals, and whether both flights are on one ticket or two.
If your connection is on a single ticket (one booking, often one or two airlines in the same alliance), the airline sets a minimum connection time and will usually protect you if a delay makes you misconnect. If you booked two separate tickets, you are self-connecting, and the buffer is entirely your responsibility.
Suggested connection times by terminal pairing
These are practical minimums for a single-ticket connection. They fold in the airline minimum plus the time to change terminals and re-clear security. Add more at the morning peak (05:00 to 08:00), when security at T3 and T5 is busiest.
| Your connection | Suggested minimum | Why |
|---|---|---|
| Same terminal (T2 to T2, T5 to T5, etc.) | 60 to 90 min | No terminal change, but you still re-clear security |
| T2 to T3 or T3 to T2 | 75 to 90 min | Linked by an underground walkway with travelators |
| Central terminals to or from T5 | 90 to 120 min | Free transfer bus or free Heathrow Express segment |
| To or from T4 | 90 to 120 min | T4 is a separate satellite on the south side |
| T4 to T5 (or T5 to T4) | Up to 120 min | The longest transfer at Heathrow |
| Separate tickets (any pairing) | 3 to 4 hours | You collect bags, re-check in and re-clear security |
Heathrow's own guidance is to allow at least 60 minutes to transfer between terminals, and up to 90 minutes between T4 and T5, on top of the time you need at the gate.
Do you re-collect your bags and re-clear security?
On a single ticket with your bags checked through to your final destination, you do not touch your luggage at Heathrow. It transfers automatically behind the scenes. You do, however, re-clear UK security screening before reaching your onward gate, because every departing passenger at Heathrow goes through security, even in transit. Since January 2026 all four terminals use CT scanners, so liquids up to 2 litres can stay in your bag, which speeds the process up.
On separate tickets it is different. You clear UK immigration (passport control), collect your checked bags from the belt, walk to the onward airline's check-in, drop your bags again and then re-clear security. That is why separate-ticket self-connections need 3 to 4 hours, not 90 minutes.
Changing terminals
You cannot walk between T4 or T5 and the rest of the airport. T2 and T3 are the exception: they are joined by an underground pedestrian walkway with travelators, so a T2 to T3 move is on foot.
For every other pairing, use the free inter-terminal transfer. Free buses connect all terminals and run 24 hours a day, every few minutes. Connecting passengers can also ride the Heathrow Express free between the central terminals and T5. Allow 15 to 20 minutes for the bus itself, plus waiting and walking time at each end.
Self-connecting on separate tickets
Booking two cheaper flights that are not on one ticket can save money, but you carry all the risk. If the first flight is late and you miss the second, neither airline has to rebook you or refund you, because they never agreed to carry you the whole way. You also have to clear UK immigration to reach the bag belt, which means you may need a UK ETA or a visa even though you are only passing through. See our guide to Heathrow entry requirements.
To self-connect safely, give yourself 3 to 4 hours between the scheduled landing and the next departure, check the onward bag-drop cut-off (often 60 minutes before the flight for long-haul), and factor in the terminal change if there is one.
More
More: Overview, Facilities, FAQs.
Frequently asked questions
Is 90 minutes enough to connect at Heathrow? For a single-ticket connection within the same terminal, usually yes, since your bags are checked through and you only re-clear security. If you have to change terminals or it is the morning peak, aim for 2 hours.
Do I go through security again when connecting at Heathrow? Yes. Every departing passenger re-clears UK security, even in transit. Your checked bags transfer automatically on a single ticket, so you only carry hand luggage through.
Do I collect my luggage when connecting at Heathrow? Not on a single ticket with bags checked through to your final destination. On two separate tickets you collect your bags, re-check in and re-clear security, which is why you need 3 to 4 hours.
How do I change terminals at Heathrow between flights? Use the free inter-terminal transfer bus, which runs 24/7, or the free Heathrow Express segment between the central terminals and T5. Allow 15 to 20 minutes plus waiting time.
How long should I leave if I booked two separate flights through Heathrow? Allow 3 to 4 hours. You must clear immigration, collect bags, re-check in and re-clear security, and neither airline protects you if you misconnect.
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Last verified August 2026 by the Heathrow Airport Guide editorial team. Prices and timetables change, so confirm the specifics on the official Heathrow Airport website before you travel.