Commuters in London are paying the highest fares in the world. The warning from MPs in today's Evening Standard reveals major cities, including New York and Berlin have cheaper single fares than the Oyster Card.
Millions of Oyster card users will be able to check their accounts online.
The new service is available for season ticket or Oyster pay as you go users, and allows them to look back over their journey history and fares paid.
Transport for London says passengers who register for the new system will find it easier to check that they have always touched in and out on their journeys.
It's also hoped it'll mean a simple process for passengers to download their journey history and use the information to claim for work expenses; rather than having to contact the Oyster help desk to ask for a printed journey history to be posted to them.