Heathrow Terminal 5- walking underground tunnel between gates, anyone walked??

Just look at this guide and it will show (and tell) you. If you scroll down, you can see a map of the walkway, then farther down it shows you more information on the walkway specifically (including how long it takes to walk between the gates (approximately 5 min. each). So it is definitely doable. https://www.heathrow.com/content/dam/heathrow/web/common/documents/at-the-airport/accessibility-and-mobility/before-leaving-home/terminal-5-arrivals-guide.pdf

I had a very long layover and spent quite a bit of time on the walkways between A and C for terminal 5. It's quite a bit of walking but I had the place pretty much to myself. You go down to level -4. I find walking more restful than sitting in a crowded waiting room. I think it was about a 10 minute walk between A and B and then again between B and C.

My husband and I have been known to use the walkway. It's nice to be able to stretch our legs after a long flight. We don't use it if we have a tight connection. We are fast walkers, never use the moving walkways, and we beat the posted timings that are displayed along the passageway. I am 65 and he is 74, if that helps.
When we first began using the walkway we we usually the only ones, but the last time we were there, we saw quite a few people.

We’ve done it when time is not crucial. It’s actually quite nice after being on a long flight.

Re: Mardee- Thank you so very much for the map link! It’s soooo helpful! I completely missed it when searching through the Heathrow website.

Re: LizLynnwood, Debra & Patty- Thank you for sharing first hand ‘feet in the tunnel’ experience! We always have a 9 hr flight and possibly long layovers, depending if flights are on time or not. I much prefer to walk after sitting for so many hours but DH takes a bit of convincing. We can have a wager; I’ll take the tunnel and he can take the tram and we’ll see who reaches the gate first. I’d be happy to lose 😊

At one time the T5 walkway was effectively staff and emergency use only, although I don't recall if it was expressly banned. Then it became more for public use, not particularly promoted at first but signage has now been improved and it is now presented as an alternative.

For people who can walk at a reasonable speed it will on average be quicker than taking the shuttle unless there would be only a short wait for one. I always walk on arrival to stretch my legs if nothing else

Diane, I'm glad it helped - it actually helped me, too, since I will be traveling to LHR for the first time in March and leaving from there in April. In the past, I always flew into Gatwick. It was very hard to find, I will admit - I had to do a search from Google and that's how I found it. There is one guide for each terminal, and now that I've found them all, I am definitely bookmarking them for future use! :-)

I have always wanted to try walking the tunnels, but I was worried about getting lost and ending up in the wrong place. Is it really well-signed now?

We walked it this year. It was well-signed. There were an incredible number of moving walkways...we wished we had known how many we'd encounter because we would have kept count! It made us chuckle as each new one appeared.