Originally Posted by
serpens
That's just within the airport, right? Is Oyster tap-on tap-off, so there is no charge within Heathrow but a charge if going to Hatton Cross or further?
Correct - Oyster or contactless, for travel between any of the three LHR stations. Starting or ending your journey at Hatton Cross is chargeable as normal. See
https://tfl.gov.uk/fares-and-payment...le-fare-finder for confirmation.
Hatton Cross is, however, the official connection point for travel from either T5 or T123 to T4, and you do not pass a gate line at Hatton Cross to do that, so changing at Hatton Cross for those journeys must be free.