Heathrow Terminal 5 Underground Walkway

I used it a couple of years ago and it's still shown on the airport's website map (at level -4 using the lift from T5A departures area, the same lift you'd use to go down to the A-B-C trains at level -2), so presumably you still can. I don't recall it saving any time though, but it was uncrowded. There were travelators for part of the walkway.

Yes, you can use it to walk between A, B, and C. There are detailed instructions on access on Flyertalk, in the British Airways Forum. I will see if I can find that and post a link.

Trains come frequently except very early hours.

But they can be delayed. We almost missed our British Airways flight back to the US from the C gates because we were in 5B and waited 16 stressful minutes for the train ( I timed it). I saw the entrance to the pedestrian tunnel then but did not know if it was OK to use it.

Here is the link to the guide ( for departing passengers):

https://www.flyertalk.com/forum/british-airways-executive-club/1578945-lhr-terminal-5-passageways-pictorial-guide-departing-passengers.html

It has a link to the separaaate guide for arriving passengers.

Yes, you can use it. We have done so the last few times we had to change between A,B, & C gates as late as this year. It is a refreshing change between flights. It is a decent walk.

It has always been publicly accessible, although only in more recent years has it been signed and made easier to follow. It's generally quicker to/from T5B than the transit unless you are lucky just to get one.

Terminal 2 operates with only a walkway, so maybe there is some influence from that.

Is it possible to move freely back and forth between the three sections (A, B, and C)?

As I understand the Flyertalk information, there are two passageways, one for arriving passengers and one for departing. If one wants to use the passageway to connect flights (a long haul from the US and a shorter flight to the Continent, all on BA), does it matter which one we use? I know we have to go through security when coming off a flight to the US and connecting to a flight to the Continent. I assume that upon deplaning from the US flight, we proceed to 5A because our next gate will not be posted yet; if we use the walkway will we be channeled through the security checkpoint at some point?

Or should we just follow the regular “Flight Connections” path on arrival and then use the passageway to get to our next gate (if it is not in T5A)?

You can clear security in the satellites (C or B) only if your arriving plane and your departing plane both have gates there. Otherwise you have to clear security in A. This is because on arrival at a satellite you only have access to the northern transit or passage, which does not connect to A departures but immigration or connection centre only.

Thanks, Marco. I am glad I asked.

Our flight from Seattle usually arrives at 5C and we won't know the gate for our next flight, so we will just use the regular Flight Connections route to 5A and clear security there. We don't want to end up on a one-way route to Immigration!