After receiving a waiver from the FCC, it looks like AT&T has flipped the switch on Wi-Fi calling. All you folks with an eligible plan and device running iOS 9 can go into Settings and flip the switch.
We tested it here in the office and Wi-Fi calling through AT&T is indeed working. Once you turn the feature to on (it’s under Phone, Wi-Fi Calling), you can just make calls as you normally would. As the name suggests, Wi-Fi calling will allow subscribers to make and receive calls over Wi-Fi. If you have poor reception at your house, this is a huge deal.
Once you do flip Wi-Fi Calling on, you’ll have to go through a few steps and a short waiting period, including entering an emergency 911 address.
Update: We turned on Wi-Fi Calling, and it works great. Unfortunately, AT&T handles Wi-Fi Calling a bit differently, which means you likely won’t get handoff capabilities when going from Wi-Fi to cellular. AT&T told us that it depends on network coverage in the area you live. If HD Voice is available when your Wi-Fi connection is lost, the call will handoff no problem. If not—like where we are in Irvine—your call will drop. The only time your call will continue is if you’re making a 911 call. Here’s a coverage map to see if HD Voice is in your area.