The device joins the Samsung Galaxy S6 and the iPhone 6 in providing the alternative call mechanism.
The Microsoft Lumia 640 with wi-fi calling is now available on EE.
Microsoft’s latest flagship smartphone will be available through several 4GEE plans. The budget handset is free on an EE £16.99 a month two-year plan while 4GEE Extra plans for the device start at £19.99 per month.
The latest Windows Phone joins a roster of devices that carry the service on EE, including the iPhone 5s, 5c, 6 and 6 Plus and the Samsung Galaxy S5, S6 and S6 Edge.
EE is the first operator to allow mobile users to make calls as normal using wi-fi. Three currently offers the service through the inTouch app, while O2 offers it through TU Go. Vodafone will launch its service this summer.
"Losing coverage at home is a major frustration, and WiFi Calling will make a real difference to millions of customers across the UK, from basement flats in London to the most rural homes in the country," commented Olaf Swantee, EE CEO, in April.
He added: "Our customers want to be able to call and text no matter where they are, and they don’t want to have to think about which app they need to use or if their friends have a particular third party service."
EE, the UK’s largest mobile provider is in the process of being acquired by BT in a £12.5 billion deal that was recently approved by BT’s shareholders. BT will now have to submit the case to competition watchdogs for approval.