Google has announced that Project Fi is expanding to more than just Nexus phones for the first time. Subscribers to the phone service will be able to order a data-only SIM to put into a tablet. But what's more interesting is the list of compatible tablets: Alongside Android devices like the Nexus 7, Nexus 9, and Galaxy Tab S are two iOS devices: the iPad Mini 4 and the iPad Air 2. It marks the first time that Google's wireless service can be used on another operating system besides Android, albeit just for data.
It's possible that other tablets (or even phones) will work with the data-only FI SIM, Google seems to believe that anything that's unlocked and works with T-Mobile's bands should work. These SIMs will just operate on T-Mobile's network instead of doing the trick that phones can do: pick between either Sprint or T-Mobile depending on which carrier has better signal.
No per-device fee
As Android Police points out, the nice thing about Fi's tablet service is that Google won't charge an additional device fee for your other products. Other carriers, as a rule, do charge a per-device fee. Instead, you'll just pay out of your $10/GB standard data buckets, pro-rated more if you go over your plan or refunded back if you don't use it all. There is a catch, though, and an unfortunate one: you can't use these data-SIM devices for tethering. Using a tablet as a Wi-Fi hotspot is way more convenient than using your phone, if only because it has a much larger battery.
If you are a Fi subscriber, you can order up to 9 data-only SIMs. If you're not a Fi subscriber, you need to get in line for the early access program at Google's site. Take note, however, that you can't get this $10/GB data for your tablet without also paying for the $20/month voice and text plan that goes with the normal Project Fi service for Nexus devices.