Originally Posted by
the-doctor
I stand corrected. Is that a recent thing? I usually get through-tickets from outside London, or discounted advance fares so I can't say I've ever tried tapping on/off...but I distinctly remember the announcements that 'Oyster cards are not valid on Heathrow Express services'
I usually take the Elizabeth Line so can't recall what it's like coming off the Heathrow Express at Paddington and if you need a different ticket there but getting on at Heathrow the same platform is used so you tap in the same way.