The first few months of this year were filled with rumors regarding Google and whether they were essentially going to begin operating as an MVNO. By April though, those rumors were realized and Google announced the launch of Project Fi as an invite only service which made use of networks provided by both Sprint and T-Mobile. Since then however, the rolling out of the service has been slow going although it has been going. Invites have largely been made more widely available and now we are starting to see a wider lists of compatible devices.
When Project Fi first launched, this was a service which was only usable by owners of the latest Google handset, the Nexus 6. Now though, a new support page has gone live and details that tablets will soon be able to make use of a Project Fi connection as well. In fact, it seems Project Fi is now available with a number of devices which make use of a data-only connection.
In terms of the details, it seems that if you already have a Project Fi account you can request additional data-only SIM cards which can then be used in compatible tablets (and some non-tablet devices). At the moment, the list of compatible tablets is a little limited with the only options stated as the Nexus 7 - K009 (US LTE), Nexus 9 - 0P82300 (US LTE), iPad Air 2 - Model A1567, iPad mini 4 - Model A1550 ad the Galaxy Tab S - Model SM-T807V. Similar to the phone plans, data charges are charged at the same $10 per GB rate and you will only be charged for data that you use. In terms of the rest of the details, there is not too much to go by way of a formal announcement. An announcement of sorts has now gone live in the Google Support forum which does detail the new service and from the looks of it, there are no additional charges for ordering the data-only SIM cards or adding devices to a plan. The forum post also does make it clear that they are looking to expand the device compatibility going forward, although no time frame was provided on this point.