The appointed agency will be responsible for handling Sony Mobile's TV, digital and social media, outdoor and print work.
McCann London handles Sony Mobile's global advertising business and their relationship is not thought to be affected by the review.
Iris Worldwide currently handles the account but the agency has declined the repitch. The agency has handled the account for the past three years.
However, Iris has worked with Sony Ericsson for the past 14 years and was one of the agency’s founding clients.
Iris will continue to work with Sony Mobile on a global basis across digital, social media, retail and channel marketing, experiential marketing, branded content development, sponsorship activation and trade advocacy programmes.
Ian Millner, the global chief executive and co-founder of Iris, said: "As part of their continuing changes, Sony Mobile UK has asked our London operation to participate in a creative pitch later this year as they look to build on the trajectory of success for the brand in the UK.
"After careful consideration, however, we have decided that we should concentrate our talent and energy on our other clients both inside Sony and outside."
Iris was behind Sony Mobile's recent digital campaign around its Xperia Z model. The agency has also increased Sony Mobile's Facebook page from 80,000 fans to over 451,000.