Transferring between Heathrow's four terminals is free, either by the inter-terminal buses running 24 hours a day or, between T2/3 and T5, the free Heathrow Express segment. Allow 60 to 90 minutes for a self-connecting transfer, and up to 90 minutes if you're moving between T4 and T5, the two terminals furthest apart. Checked 2026.
Why you might need to transfer
If your airline booked you straight through on a connecting itinerary, ground staff usually route you automatically and you may not leave the secure zone at all. This guide is for self-connecting passengers: separate tickets, sometimes on different airlines, where you've booked two flights yourself and need to move between terminals on the ground, potentially clearing security again.
Heathrow's four operating terminals are T2, T3, T4 and T5. There's no T1 anymore; it was demolished some years ago.
The two ways to transfer
Free inter-terminal buses
Free shuttle buses connect all four terminals and run around the clock, so they're the fallback option whatever time your connection falls. Follow the "Flight Connections" or terminal transfer signage inside each terminal, or ask at any information desk. Because these are road-based buses moving around the airport perimeter, journey times can vary with traffic and time of day, so build in a buffer rather than cutting it fine.
Heathrow Express (free segment)
If you're moving specifically between T2/3 and T5, the Heathrow Express train covers that stretch for free as part of an inter-terminal transfer, and it's markedly quicker than the bus since it isn't affected by airside road traffic. This doesn't extend to T4; a T4 connection still needs the bus network.
How much time to allow
Heathrow's own guidance is to allow 60 to 90 minutes for a self-connecting transfer between terminals, and up to 90 minutes specifically for a T4-to-T5 move, the longest transfer on the site. Build this into your connection time when you book two separate flights, on top of however long security and any immigration re-clearance takes at the second terminal, since a self-connecting passenger typically has to go through security again at the departure terminal.
If you're not self-connecting and your whole itinerary is on one ticket, check with your airline what's actually required. Some through-connections on the same ticket still involve a terminal move, just with staff assistance and a tighter, managed process rather than the general passenger route described here.
If you need extra help
Passengers with mobility difficulties or other support needs can request assistance for a terminal transfer the same way as for any other part of the airport; contact your airline in advance, or ask airport staff for the impairment and mobility support option at the transfer point.
Practical tips
- Check which terminal each of your two flights actually departs from before you fly. It's easy to assume both are at the same terminal when they aren't, and mismatched terminals are the single biggest cause of a missed self-connection.
- If your layover is under about two hours, weigh up whether a self-booked separate-ticket connection through two different terminals is realistic, given the 60-to-90-minute transfer allowance plus security.
- Keep your boarding pass or booking confirmation to hand; terminal transfer signage and staff will often ask to confirm your onward terminal before directing you.
- If the T5 to T2/3 Heathrow Express segment is available for your transfer, take it over the bus when timing is tight, since it isn't subject to airside traffic delays.
Related reading
If you're arriving on one flight and departing on another with real time to spare, see our guide to leaving Heathrow during a layover, or connection time at Heathrow for how much time to allow more generally. For getting into central London on a shorter layover, see our guide to central London journey options.
FAQs
How do I get from Terminal 4 to Terminal 5 at Heathrow?
By the free inter-terminal bus, which is the only option for a T4 transfer since the Heathrow Express doesn't call there. Allow up to 90 minutes, the longest of any Heathrow terminal transfer.
Is the Heathrow Express free between terminals?
Yes, for the T2/3 to T5 segment specifically, as part of an inter-terminal transfer. It doesn't cover T4.
How long does it take to transfer between Heathrow terminals?
Heathrow's guidance is 60 to 90 minutes for a self-connecting passenger, rising to 90 minutes for a T4-T5 transfer specifically.
Do I need to go through security again when transferring terminals at Heathrow?
Usually yes, if you're self-connecting on separate tickets, since you'll typically need to clear security again at your departure terminal. Airline-booked through-connections may differ; check with your airline.
Is there still a Terminal 1 at Heathrow?
No. Heathrow now operates four terminals: T2, T3, T4 and T5.