Sprint is taking another page from T-Mobile's playbook and announced that it will be rolling out Wi-Fi calling to the latest iPhones running in its network.

This should be good news for users of the iPhone 6, iPhone 6 Plus, iPhone 5s, and iPhone 5c. Although Sprint is the third biggest mobile carrier in the U.S. - fourth, by some accounts - the company is largely criticized for having the worst network coverage among the Big Four. With Wi-Fi calling available, iPhone users can have much more respite than Sprint subscribers with Android and Windows devices, especially when they are in areas where Sprint's network is particularly sluggish.

"Wi-Fi Calling is like a major expansion of our network, allowing Sprint customers to get coverage anywhere they have Wi-Fi connectivity," says Sprint senior vice president of product development David Owens. "Traditional wireless technology has some limitations in places like basements and high-rise office buildings. Wi-Fi expands our customer's connectivity in a big way."

Sprint says Wi-Fi calling will not count against the user's call and data limits and will be available for iPhone users traveling to other countries, although international Wi-Fi calling will be subjected to CDMA international calling plan rates but not roaming charges. Wi-Fi calling is expected to roll out to the four latest iPhones "over the next week," so users don't need to worry if they don't have the new feature yet.

Apple recently released iOS 8.3, the latest version of its mobile platform, which brings support for Wi-Fi calling. To activate Wi-Fi calling on an iPhone, users will have to download iOS 8.3 and wait for the software update dubbed Carrier Version 19.1 from Sprint to arrive on their devices. Once both updates are installed and working properly, users can simply open the Settings on their iPhone and toggle "Allow Wi-Fi Calls" under Phone.

Over in Europe, British carrier EE also announced Wi-Fi calling for the iPhone 6, iPhone 6 Plus, iPhone 5s, and iPhone 5c. Users can turn on the feature using the same procedure outlined by Sprint, but they will have to wait up to 24 hours for EE to service their devices.

Wi-Fi calling is fast becoming a viable alternative to customers who are dissatisfied with poor network coverage. T-Mobile was the first network to offer Wi-Fi calling, but smaller cellular providers with a focus on Wi-Fi calling are slowly gaining ground because of cheap plan offerings. Google is also planning to launch its own Wi-Fi wireless service to limited markets in the future.

However, Wi-Fi calling is not a viable replacement to cellular calls, as it requires users to keep connected to a single Wi-Fi network throughout the entire call. As for Wi-Fi calling on an iPhone, some users point out that turning on Wi-Fi calling on their iPhones deactivates Continuity and prevents them from receiving calls, messages, and files from their iPhones to their Mac or iPad.

Photo: Kārlis Dambrāns | Flickr