Now you can place international calls wherever you are on the globe, if you have an iPhone 6, 6 Plus, 6s, 6s Plus, or SE, and are an AT&T customer.

All you have to do is to install iOS 9.3, after which AT&T's WiFi calling service will activate in your phone, allowing you to place international calls, from any WiFi-serviced location in or outside US, and that too without any additional roaming charges.

So, even if you don't have any cellular coverage, the WiFi-connected device will enable you to make or receive calls with your usual plan rates.

AT&T sent free texts to all its users to inform them that they now can use WiFi for international calling even from outside US. "Use Wi-Fi Calling to talk and text over an active Wi-Fi connection. Wi-Fi Calling lets you talk and text from indoor locations where it's hard even for a strong cellular signal to reach. Wi-Fi Calling can be used in the Domestic Coverage Area (U.S., Puerto Rico, and U.S. Virgin Islands) and from most international countries," the message said.

This sounds like welcome news to frequent travelers and globe hoppers, as this can save them from exorbitant international roaming charges.

When an international traveler's device is connected to a local WiFi, his phone is rerouted through internet, and calls or text are exchanged using the same phone number, without any need for special access codes.

The first-timers will have to go through a setup process before the service is usable on their iPhones. Here are the general instructions for enabling WiFi on your device: Go to Settings -> Phone -> WiFi Calling - Switch On.