T-Mobile and Sprint. By partnering with US Cellular, Project Fi is able to add a third network provider whom they can switch from to provide the strongest possible signal strength for its customers at certain locations and instances. Through this partnership, Project Fi will be able to expand its cellular coverage; especially since US Cellular has a network reach of up to 23 states.
According to Google, Project Fi uses an intelligent technology that analyzes the speed from each network. With this data, it lets users automatically connect to the network that is fastest at the location where he/she is in. Access to US Cellular networks will automatically be available over the next few weeks.
As of this writing, Project Fi is compatible with three devices namely the Nexus 6, Nexus 6P, and Nexus 5X. They offer a service plan with a rate of $20 per month and includes unlimited talk, text and international text. To add data, an Add On of $10 per GB per month may be purchased. Any unused data gets refunded to the customer. On the other hand, when an individual goes over the data allotment, a $10/1GB charge will be given. When traveling internationally, customers may use their data in over 120 countries at the same rate; however the speed will be reduced to just 256 Kbps. There is an option to make calls to the US for free through Wi-Fi.