Just wanted to add my experience so far to this thread. I've traveled a bit with Fi and it has worked pretty well. Places I've been to include Guam, Hong Kong, UK, Finland, Estonia, Ukraine and Turkey. Those were all before high speed data was offered, so I'm looking forward to my next trip where I can try out the faster data.

And despite the warnings, I'm using my Fi sim on an iPhone 6s and haven't really run into any problems yet, only a few annoyances.

Thanks for the replies. I manged to source a nexus 6 from a buddy who is using it on Ring Plus and I'm wondering if I can "borrow it" to set up the Fi service and just use it with the iphone or should I get a data sim* ? After Fi is set up, can he go back to Ring Plus, or does the phone have to be active for the data sim/ Fi to work?

*I don't really need phone service, just data to use while abroad

Does the addition of 3 means you can only get high speed data while roaming on 3, not on any of the other foreign carriers?

3 isn't in a lot of countries.

The data sim can only be purchased and attached to a standard voice+sms+data Fi account. So you can have a Fi sim without a data sim but not the other way around. If you don't use the data on the Fi sim, you'll get a credit applied toward your next month's prepay bill. I don't think you can activate Fi and data sim, then cancel Fi but keep the data sim active.

I'm not canceling Fi. I'm looking to see once it's activated on a Nexus phone can I remove the sim and put it on my iPhone and can the Nexus go back to Ringplus for either the Fi or data only sim to work?

Would you mind laying out the annoyances?

My wife & I are iPhone people, and are sick enough with AT&T to consider switching. However, she hates too much "tech" and likes stuff to just work, so I'm nervous that "annoyances" are going to be a deal-breaker...

CLG

is there a way to activate Project Fi account/SIM without owning a Nexus phone?

thanks!

Googling shows that Sprint tracks the IMEI's of phones used on Sprint & Sprint MVNO. Activating a phone on Project Fi can tie the IMEI there. You'd need to remove the IMEI from your Project Fi account but don't have another Nexus to tie to Fi. Also, since the phone is already tied to a Sprint (RingPlus) number, it might have some issues activating the Sprint shadow account.

http://www.androidpolice.com/2015/11...ice-on-sprint/

https://social.ringplus.net/discussi...fi-to-ringplus
https://www.reddit.com/r/ProjectFi/c...ect_fi/cxndz71
https://productforums.google.com/for...rum/project-fi
https://www.reddit.com/r/ProjectFi/c...lan_it/cypqh56
https://www.reddit.com/r/ProjectFi/c..._fi_to_sprint/

Once you have it setup, things actually work pretty well. The biggest annoyance for me is that you need to use Hangouts for SMS messages, I prefer having everything in Messages, but Hangouts works well enough, and very few people I txt with don't use iPhones, so the majority of the time I'm using iMessage anyway. :) This isn't to say that using Messages to send SMS won't work, it is just that you will see extra control characters appended to the end of your message.

Another annoyance is that MMS messages sent via SMS (not iMessage) seem to have problems. I've had images sent via Hangouts arrive fine (although at low res, but that's a known issue), and images/videos sent using iMessage are fine. But I think when ExpertFlyer sends me an alert using the email gateway, I get an MMS delivery failure message from Project Fi. It doesn't really bother me as I get the same information in emails anyway.

What else... missed phone calls will not show up in your Hangouts history, but they will show up in your iPhone history. Wifi calling is not as integrated as it was with T-mobile, but if connected to wifi, you can still send/receive calls and txt messages through Hangouts (not sure if the regular phone app would ring though). I think I had to set the APN settings to get data to work, but that was a one-time thing. Lastly I also set the Enable LTE option for data only since Project Fi doesn't support VoLTE, and if you set your phone to use LTE for Voice & Data, then it may have problems completing calls.

Other than that, tethering works well, data roaming works well, and this past weekend I got LTE when in Costa Rica with speeds of 15Mbps down and 6.5Mbps up!

If you have any other questions, let me know. Project Fi has been really great for my usage patterns!

The only thing that's holding me back is the amount of mobile data that I use.
I'm still holding on to my Verizon unlimited data and have been keeping the
monthly usage below 70gb. Since Project Fi charges $10 per GB, that's
$700 for me. However, I've been testing to see possibly surviving with just
5gb to 10gb per month. If I can survive that, I guess I can make the switch
over to Project Fi. (which will save me a TON of $$$ when I do international
roaming)

Once again thanks for the replies. I looked a bit more and like the above poster said, if you try going back to sprint it might mess up the connection, and that's a risk one has to to take. I haven't fully committed to doing that just yet, and always keeping an eye out for a nexus deal. In the mean time, I may just look at buying a UK 3 sim and use it for data.

@dyung - Have you swapped Fi out of your iPhone to Verizon? I swapped mine and Verizon's LTE settings didn't seem to populate so I had to a network reset. No big deal except having to reconnect and enter wifi passwords.

Sorry, I haven't switched carriers since switching to Fi.

Why not just use the Project Fi sim card only when traveling? If you don't use it at all, you would only be charged $20+tax/month. With the amount of data you use, Project Fi probably be quite a bit more expensive for you.

That's what I've been trying to find out. Can I use Project Fi one month,
then suspend it the next month... then activate it again the next month?

I intend to use the Project Fi SIM in a non-Nexus phone.(most likely my
Galaxy Note 5 or S7) I was told on by Project Fi that the suspending
and reactivating of the Project Fi acct has to be done on a Nexus phone
only. Is this correct?

Thanks!