The sprawling search company would sell the service directly to consumers, according to The Wall Street Journal, which cited unnamed sources. Tech news site The Information reported on the deals earlier on Wednesday.
Google is heavily involved in mobile through its Android operating system, the world's most widely used mobile OS, as well as through selling mobile advertising, and is pushing to make more radio spectrum available for wireless services. But the partnerships with Sprint and T-Mobile would bring the company into the cellular business itself, offering Google phone plans directly to consumers.
The deals would make Google an MVNO (mobile virtual network operator), a carrier that doesn't build or operate its own network but sells services that run on the partners' infrastructure. Sprint is the third-largest U.S. mobile carrier and T-Mobile is the fourth largest.
As a powerful and well-heeled newcomer, Google might disrupt the cellular industry, just as it has the wired broadband business with its Google Fiber service. The U.S. mobile industry has been wracked by new business models and falling prices in recent years.
It's not clear whether the company will launch a full-scale national effort or a more limited rollout. There are terms in Google's contract with Sprint that would allow for renegotiation if Google draws a huge number of subscribers, the Journal said.
A Google mobile service might rely partly on cheap or free Wi-Fi networks where available, the Journal said. That's a likely strategy for Google, which has called for making more unlicensed or lightly licensed spectrum available for mobile services. The company has advocated the use of both unlicensed "white spaces" frequencies in the TV band and a band around 3.5GHz that would be shared with the military and other users.