Adding a 1-time Zone 3 trip from a Zone 1-2 PAYG Oyster card
Hi - I've searched and not exactly found the answer for my particular situation. We will be getting PAYG Zone 1-2 Oyster cards that I will load with 30GBP upon arrival at Heathrow.
The only time we might need to venture into Zone 3 is IF we decide to visit Gods Own Junkyard in Walthamstow. We are still undecided and otherwise all transit will be in Zones 1 - 2.
How do I add the single fare to my Oyster if we decide to go? I don't understand since I will be topping up my Oyster if we run low on GBP, why wouldn't the extra fare just come out of my Oyster balance?
Thank you for clarifying!!