US operators AT&T, T-Mobile and Verizon Wireless have scaled back their plans to launch their own mobile payments network, according to the Wall Street Journal (WSJ). The WSJ report claims that the trio have decided that their Isis joint venture – which would see customers maintain accounts directly with their mobile operator, rather than a credit card company such as MasterCard or Visa – is “too difficult and time consuming” in its current format. Instead, the trio now hope to establish a mobile wallet that can store and exchange the account information on a users’ existing credit card. In fact, the group is now talking to Visa and MasterCard to have them take part in the system they will embed in phones.

Formally announced in November last year, Isis initially planned to launch services in 2012, targeting a combined mobile subscriber base of more than 200 million customers. Discover Financial Services was chosen as the venture’s payment network partner, but the WSJ report claims that many merchants were “cool” to the choice of Discover as it is a small player that lacks the reach of Visa and MasterCard. Isis also counts Barclays as a current partner. The WSJ report suggests that a first trial will still happen next year with the Utah Transit Authority, allowing people to pay by tapping an electronic fare reader with an Isis-enabled phone using NFC technology.

The paring down of Isis’ ambitions will be welcomed by operator rival Sprint, which is expected to launch its own NFC services this year. Meanwhile mobile software vendors and device manufacturers such as Google, RIM, Apple and Nokia are all ramping up their efforts in this space.