The T5 to T3 Transfer at Heathrow: A Photo Guide
Heathrow T5 to T3 airside transfer explained - purple signs, free connections bus every 6-10 minutes, and newer security that skips the liquids unpack.
Connecting from a British Airways flight at Terminal 5 to an American Airlines departure at Terminal 3 sounds like the kind of layover logistics that inspires anxiety. The terminals are separate buildings a mile apart, you need a bus to get between them, and you still have security to clear on arrival. This was especially the case when Heathrow was still using older scanners that required electronics and liquids be removed.
On my recent RTW trip - coming off a BA Copenhagen flight and heading to the AA Flagship Suite on LHR-ORD - I did it in only 25 minutes. Here's exactly how.
The Route
This applies to same-ticket airside connections. If you're on separate tickets with checked bags, you'll need to clear UK immigration and transfer landside, which is a different process entirely and requires considerably more time.
For a through or connecting ticket connection, the route is:
- Deplane at T5 and follow the purple flight connections signs. If you need it, an arrival board will display relevant info for your connecting flight
- Escalator down to the bus level
- Look for the dedicated flight connections bus to T3. It runs every 6 to 10 minutes and the next arrival will be displayed on an overhead screen.
- Security at T3 on arrival
- Airside into T3 departures
You pass through no UK immigration and no bag collection is needed. Your bags transfer automatically if they're checked through on a single itinerary.
The Purple Signs
The first thing to note about transferring at London Heathrow is that the signage is really good. At T5, purple "Flight Connections" signs appear immediately as you deplane and stay consistent all the way down to the bus level. There's no moment where you need to make a judgment call about which direction to go - just follow the signs, take the escalator down, and you're at the bus in a matter of minutes. If needed, there are plenty of staff in purple vests to help with the process.
This is worth saying because Heathrow has a reputation for complexity, and the T5 to T3 connection looks intimidating on paper.
The Bus
The flight connections bus is a dedicated bus service that runs between T5 and T3 (and other terminals). It's free, runs frequently, and the ride itself is only around 10 minutes. You board at the bottom of the escalator and while seating was limited, it never felt crowded.
On my connection the bus left within a few minutes of arriving at the stop. Your experience may vary depending on time of day and how many other passengers are making the same transfer, but the frequency means you're rarely waiting long.
Security at T3
On arrival at T3 by bus, you go straight into a dedicated flight connections security checkpoint. This is separate from the main T3 departures security and is specifically for transferring passengers. For those with status or traveling on premium tickets, there are no priority lanes. In practice, this isn't an issue.
The machines here use the new CT scanning technology that doesn't require removing liquids or electronics from your bag - instead everything goes through in a single tray. The queue was short and the whole process took a few minutes. It's a noticeably smoother experience than transferring through Heathrow in the past. Once through, you take an escalator down to reach T3's airside and can head directly to your gate or lounge.
All in 25-Minutes
My T5 to T3 transfer at 11am on a weekday took only 25 minutes. That included following the signs, a short wait for the bus, the ride, and clearing security.
The official Heathrow minimum connection time for T5 to T3 on a single ticket is 90 minutes, which gives you substantial buffer for delays, slower queues, or a longer walk to a remote gate at T3. Some T3 gates are a significant walk from the main terminal, so factor that in when the gate is posted prior to departure.
25 minutes is the floor on a good day, so keep that in mind. But it is reassuring to know the transfer itself, when things are moving smoothly, is genuinely quick.
Part of the Around the World on Miles series.