Some good news!
A few years ago TfL introduced retrospective weekly capping for blue adult Oyster cards without any discounts. This meant that each days journeys were run through the same back-office function as is used to calculate daily and weekly charges for contactless cards and devices. At the time it was stated that discounted Oyster cards would follow, but that seemed to be taking forever. Until now.
It actually started on December 7th 2025. I noticed an unexplained refund when looking at someones journey history and asked the question. I then tried it myself and lo and behold a refund came back. I’m not quite sure why they haven’t sought to publicise this more widely, but here it is.
So, what happens? Each day the journey touches are processed through the back office. This calculates the best combination of zonal caps and extension fares and arrives at a total. If that is less than the amount actually charged by the Oyster system then an adjustment is put in a queue. At the end of the week it also works out the best combination of weekly cap and extension fares and again compares that to what has been charged throughout the Monday to Sunday week. The adjustments are totalled each night and if they exceed £1.50 a credit is put on the Faster Universal Load (FUL) system to be picked up next time the card is touched on a reader as part of a journey. Two weeks after the first un-processed adjustment is raised any amount outstanding is added to FUL.
An example to demonstrate this. If a tourist lands at Heathrow Airport and takes the Piccadilly line into zone 1, then spends the rest of the day travelling around zones 1-2 the Oyster system will charge up to the zones 1-6 cap at £16.30. The overnight process will determine that the best combination is a zones 1-2 cap of £8.90 plus a zones 6-3 Underground extension fare of £3.40. If the tourist had reached the full zones 1-6 cap then a credit of £4.00 would be added back to the card the next day.
In the extremely unlikely event that the back-office calculation produces a higher figure, no attempt will be made to recover the difference. There is no method to retrospectively deduct an amount from the PAYG balance.