EE and Vodafone are in talks with Transport for London to allow commuters to use their NFC-enabled phones to pay for tube fares.
London Underground ticket barriers are capable of reading the NFC chips in smartphones and contactless payment cards, much like those on the buses in the capital, but a system of payment is yet to be approved.
Travellers in London can already use their phones or NFC cards to pay for journeys on buses and trials will soon start on the Tube network too, reports the Financial Times.
Trials will initially be based on a pay as you go system, with networks said to be offering tube fare payment through their mobile wallets. You pre-load cash on their applications and then use it to pay at the ticket barrier.
A "person familiar with the plans" also told the FT that operators could eventually allow customers to buy weekly or monthly travel cards.
Transport for London claims that the barriers would still need to be switched on to work with smartphones. "The upgrade we have made to our readers to accept contactless payment cards also makes them capable of accepting suitable payment applications on mobile phones," said Shashi Verma, TfL's director of customer experience.
"We are doing some testing to see how the devices perform on the system and welcome any new payment technologies that meet the relevant industry standards and enable sufficiently fast transactions speeds."