Google's Project Fi, has added a 4th network partner in "Three." Three is the first official European wireless operator to partner with Fi, and 4th partner overall. The other partners include T-Mobile, Sprint and US Cellular.
With the addition of Three, Project Fi users will now be able to use their phones while traveling to over 135 different countries with data at 3G or 4G speeds depending on what is available in the given country. Prior to the deal with Three, Project Fi users were limited to just 2G speeds in 120 locations. At this time Project Fi is only available to subscribers in the US, although the deal with Three may lead Google to expand its wireless service into other markets.
Google's Project Fi works by automatically switching between wi-fi and cellular networks, whichever works best given your location, to place calls and text messages. Pricing for the service starts at $20/month for unlimited talk and text and $10/GB of 4G LTE data. Data charges are the same whether you are in the USA or traveling throughout another country. Any unused data you have at the end of your billing period gets refunded to your account. Project Fi is only available to users who have a Nexus 6P, Nexus 5X and the Nexus 6.