A global wireless system for smartphones from Google that supports Wi-Fi calling. Initially Project Fi, Google Fi users seamlessly switch phone and data service between Wi-Fi hotspots and cellular. Introduced in 2015, the service was initially offered for Nexus phones purchased directly from Google. Subsequently, Motorola and Pixel phones were offered, and support for customer-owned iPhones, Samsung and other brands followed. See Google Nexus
Google Fi piggybacks over the T-Mobile and U.S. Cellular networks and uses more than three million Wi-Fi hotspots.
A Cloud-Based Phone Number
Subscribers are given a phone number that can also be used to make phone calls and send text messages from their tablets and computers via Wi-Fi or Ethernet.
With no annual contract, the Basic plan provides unlimited domestic talk, low international rates in 120 countries and unlimited international texting. Each gigabyte of encrypted data is an additional $10/month, and unused bytes are credited to next month's bill. See Google Fiber