On the unlocked GSM version you can find wifi calling by going to "Settings" and in the search box type "wifi". Scroll down and you will see wifi calling. I'm on AT&T and I've had no luck getting it stay activated. I called tech support for help troubleshooting. The tech told me since this phone is listed as "unknown" in their database, activating wifi calling was not possible at this time. He did tell me that the information about this phone has been submitted, and sometime in the near future this option should become functional. Hope this helps.