O2 expects Londoners to be able to go through tube barriers and pay for products such as newspapers and doughnuts using their phone within two years.
The revelations are the outcome of a wide-ranging trial of its Near Field Communications (NFC) technology trial.
Around 500 people in the trial used the Nokia 6131, which combined the Oyster travelcard in London and a Barclaycard Visa from November 2007 to May this year.
More than two thirds of the people who took part said they were interested in having the Barclaycard Visa payment option.
The Oystercard also proved a hit with almost nine out of 10 trialists saying that they wanted to use their mobile instead of a physical travelcard.