What you need to know
- Compatible unlocked phones can use a Google Fi SIM card and get T-Mobile's 5G network.
- Galaxy S20 models are compatible with Sub-6, with the S20+ and S20 Ultra also able to use mmWave.
- Software updates will be needed to unlock all of T-Mobile's network bands.
We haven't really thought about Google Fi and its ability to offer 5G because of its historical tie to Google's own hardware and select "made for Fi" phones, which doesn't yet include any models with 5G. But as of last year, Google Fi fully supports the use of any unlocked phone with T-Mobile compatibility — and yes that means if your unlocked phone's compatible with T-Mobile's new 5G network, it will get 5G too.
As I noticed on my unlocked Galaxy S20 Ultra, as soon as I put in my Google Fi SIM card and restarted, I was able to get T-Mobile's 5G network right away. That goes for T-Mobile's nationwide(ish) Sub-6 5G network, but also its mmWave 5G network that's available in parts of a handful of cities. I happen to be lucky enough to live in a neighborhood of New York City that has access to T-Mobile's tiny mmWave network, so my first experience with T-Mobile 5G via Google Fi was actually pretty fast. (And I obviously didn't realize it was mmWave at the time of the first tweet above.)
You'll get both Sub-6 and mmWave with the right hardware.
And nope, this isn't anything new. Google announced months ago that it would support T-Mobile's 5G network when using its service in a T-Mobile compatible phone. It even says so right on the coverage section of its website: "If your unlocked phone is compatible with T-Mobile's 5G network, you'll have access to 5G on Fi."
T-Mobile's Sub-6 network is available in a vast majority of the places its LTE network is, so you'll be able to start taking advantage of that right away. Though as our friend Sascha Segan points out, the S20 series will still need a software update to give it access to all of T-Mobile's network and match the capabilities of the OnePlus 7T Pro 5G McLaren Edition.
T-Mobile's mmWave network is available in only six cities — NYC, Los Angeles, Las Vegas, Dallas, Cleveland and Atlanta — at the moment, and in most cases doesn't have much spectrum to allocate, so you're likely to see lower mmWave speeds than what Verizon's been touting. But even still, in my quick testing I was able to get roughly 125-150 mbps download and 30-50 mbps upload in NYC — two or three times better than what T-Mobile and Verizon both offer with LTE in the area.