I checked with AT&T today and entered my IMEI number for the Librem 5. The website tells me that my phone is not compatible with their network.
The cellular network list states that AT&T works, but it appears that it was only confirmed with 3G - which is ending or has ended for AT&T.
Anybody using AT&T?
I used to. The SIM I was using was activated and used on an Android before putting it into my L5, which I believe is a key step.
I am no longer using AT&T but not because of any issues with my L5 not working. Mint Mobile now, and my experience has been 99% the same. (My Mint SIM also was activated on my old android before putting in to the L5).
Edit: And to clarify, 4G did work for me. We changed to Mint probably around 5 months ago.
Fair enough. Thank you for your comment.
I have ATT and phone, texty and data work. I had a different approach: I first got the pinephone and walked with that phone to the ATT store and asked for a SIM for it. It took a while and extended discussions until they would accept that phone to my existing family plan. Once the L5 arrived, I swapped it (without telling) and it worked.
Though, shortly afterwards ATT and others shut down 3G, 2G and no calls were possible. I found the commands how to program the modem somewhere in the wiki (VOLTE) and finally after some try and error it worked and still does.
So the key is to be kinda sneaky. Noted. I appreciate your response.
This was my path as well. I am thinking of going back to Purism’s Awesim, because AT&T has now made it cheaper for me to move my phone off my family plan.
Has ended. Some time ago.
Probably need to qualify here: 4G data, or 4G calling (i.e. Voice over LTE).
Have you verified that 4G stays active during a call? (As displayed in the top notifications bar? And that the call actually connects to the other party, of course. 
)
Not sure to be honest. I think both? “4G” was still visible while on calls, that much I know.
I have used Pure Talk, an AT&T MVNO, since the beginning (well, my beginning in 2021). When I got the phone, Pure Talk was already 4G only. I purchased their SIM, did the settings all up right, and it worked immediately for standard text. After reading about why I was having the call issues, I went through the manual enabling 4G steps (which there is a program for now), but once I did that, the calls worked, and still work, pretty much fine. Every once in awhile it seems to forget it’s a phone and it needs to be restarted. But I know it’s working on 4G, not only because that’s all Pure Talk has, but also because I have it set to 4G only. Sometimes group and data messages are delayed/sketchy, but that seems to be a known problem.
Interesting. I just checked my own L5’s IMEI (BM818-A1 modem) on their website, and it passes the compatibility check. I wonder if AT&T has relaxed their stance a bit.
Good news for U.S. users who would prefer to be on AT&T’s infrastructure.
Odd. I tried twice. Third time is the charm?
Interestingly, AT&T’s Cricket Wireless brand’s IMEI check still fails (as it always has).
Is it possible that Pure Talk’s check is just an error that slips through the cracks? (The network seems to be working for @N8W , though.)
Ah! I tried AT&T’s main IMEI checker. I did not try PureTalk. That might be the issue. Which, if that the case, seems odd. Why would PureTalk be different from AT&T’s main website?
Just to be specific: 4G sign stays on during call. I tried it again and it won’t fall back to 3G (unsurprisingly since ATT had shut down 2G/3G in 2022). I can’t say for sure if data were also 4G but internet browser (Firefox) works reasonably well without wifi connection.
I went ahead and purchased a PureTalk card. Data works wonderfully. Unfortunately, I have been unable to make calls with that SIM card. I have spent a fair amount of time today holding for technical support. I have no answer from them yet.
Seems like I may have wasted $40.00 signing up for a SIM card that does not make calls with the Librem 5. Frustrating. Maybe they will give my money back.
Thought I would give a status update . . .
Yes. I was sceptical that an AT&T-based provider would work for calls (by VoLTE) on the L5.
Unfortunately, it looks like only T-Mobile or AweSim work then?
I would hold off until AweSIM is organised again and then find out which underlying MNO is being used. (Maybe someone inside Purism or outside Purism can already tell you that.)
AT&T is being used as far as I know
No need to guess. Run the command from this script and then check the Operator ID field for the MCC/MNC numbers.