Arena, part of Havas Media Group, will start working on the business immediately.
MediaCom was the incumbent. The WPP agency won the consolidated European account and retained the UK brief in 2010.
MediaCom worked on campaigns for EA games including Fifa 14, The Sims 4 and Titanfall.
Henry Daglish, the UK managing director at Arena, said: "EA is an amazing brand and we’re delighted to be working with them to help the brand evolve and grow."
The review was handled by EA through its Geneva office. Chemistry meetings took place in early February.
The gaming giant has been rebuilding after a turbulent 2013, when it cut more than 10 per cent of its workforce and was voted the worst company to work for in the US.