Optus has become the first Australian carrier to deliver commercial voice over wi-fi to its mobile consumers, offering the service through a new Android and iPhone app dubbed WiFi Talk.

The app is a free download from both the Apple App Store and Google Play, and works on devices running at least iOS 6 or Android version 4.0.
WiFi Talk uses around 300kB per minute when making or receiving a call, and around 80kB an hour when running in the background.
The service is available to both prepaid and post-paid customers, with calls and text messages charged to a user's mobile plan or prepaid balance at their regular rate.
Optus’ vice president of customer experience and delivery Amanda Hutton said it would be "the first of many exciting developments for Optus in the wi-fi calling space".
“Unlike traditional wi-fi calling applications, it uses your existing Optus mobile number when people call or text you, and [the other party doesn’t] need the app or have to do anything differently,” Hutton said.
Meanwhile, a Vodafone spokesperson told iTnews the telco's current focus was on rolling out VoLTE.
“We value a quality customer experience and while we are working to deliver native voice over wi-fi in the future, we want to ensure it is the best possible product,” the spokesperson said.
“Vodafone customers already enjoy unlimited national calls as part of most of our plans."
Telstra has previously revealed it is looking at voice over wi-fi as another way of delivering voice services to its customers in the future, but is yet to make any formal announcements.
A Telstra spokesperson told iTnews it is looking at introducing “a more sophisticated voice over wi-fi technology”.
“The solution we are exploring would offer customers a seamless dialling and call hand-over experience between our 4G mobile service (via VoLTE) and wi-fi without the need for downloading or running an app,” the Telstra spokesperson said.
“We will have more details to share in the coming months.”
It has also been heavily promoting its Telstra Air wi-fi network since its launch in late June.
Sources at Optus had told iTnews in late June that a voice over wi-fi announcement was imminent, although the telco would not be drawn on the technical details at the time.
It comes less than a week after the company announced it would close its legacy 2G network on April 1 2017.