According to https://www.theverge.com/circuitbreaker/2016/7/12/12159210/google-project-fi-three-network-international-roaming-speed , Project/Google Fi added 3/Hutchinson as a native carrier in the UK in the same way that Sprint/T-Mob/US Cellular networks provide service in the US.

One of Hutch's subsidiaries probably provides service almost everywhere in the world (except, oddly, Mexico, last I looked). But whether there's a Google/Hutch tie-in in that market another matter. A Fi data SIM should work in any Google-supported market though. Checking the bands used by the local markets (and/or the prospective device) might be a good idea.

Think I've had Fi for 4 years now. Stepping off the plane and your phone Just Works is kind of magical.

You can only activate a voice SIM in a Fi-supported phone - but the SIM will work if transferred to another phone once activated, you just may have fewer radios & lose functionality (like transparent in-call handoff between multiple carriers).

On Thu, Aug 1, 2019 at 7:03 AM Matt Corallo <nanog@as397444.net> wrote:

When using a data-only Fi SIM (which are free if you have an account, just pay the bandwidth), they always just act as a T-Mobile US MVNO and route back through the US. Still, latency aside, I've found it incredibly reliable (plus in many countries you can pick from multiple networks).

If you have an Android phone it may switch to 3UK/Hutch's global network, though I have less experience with that.

Matt

> On Aug 1, 2019, at 03:55, Tom Hill <tom@ninjabadger.net> wrote:
>
>> On 01/08/2019 03:19, Mehmet Akcin wrote:
>> Google Fi
>
> Are you suggesting Fi because of:
>
> "When outside the United States, cellular phone calls cost $0.20 per
> minute, data costs the same $10 per gigabyte (i.e. there are no extra
> data charges outside of the US), and texting is free."
>
> Ergo, relative to the countries stated, permanently roaming?
>
> I'd love to know if you've found that reliable - it seems too good to be
> true.
>
> --
> Tom