PinePhone Carrier Support
This page contains hints on setting up cellular network connectivity for specific carriers. For more general information, see Modem and carrier support. For the APN settings see PinePhone APN Settings.
To check if the PinePhone is supported on your carrier:
It is likely that there will be a few frequencies that your carrier uses which are not supported by the PinePhone. Not all of the carrier's frequencies need to be supported by the PinePhone for it to work - as long as most of them are supported, you will still get good coverage.
According to this page, AT&T's primary bands are 12 and 17 - 700ac and 700 MHz respectively. The PinePhone seems to work out-of-the-box with AT&T. Activating a SIM works. Calls and SMS messages work. VoLTE is as yet untested.
Cricket wireless is a MVNO that uses AT&T's network. VoLTE is fully supported and the PinePhone is considered a compatible device in the US by the carrier.
SimpleMobile is a T-Mobile prepaid MVNO operating in the United States. 4G LTE, VoLTE, data, and SMS all work on the PinePhone after activation. Activation can be done online without extra software or assistance, go to https://www.simplemobile.com/activation/byopcollectsim and make sure you have your SIM card and IMEI ready.
Sprint is currently not supported due to unknown reasons. Any input regarding this issue is highly appreciated.
According to this page, T-Mobile's primary frequency band for the United States is 12 (700ac MHz).
T-Mobile's bands and protocols are summarized on this page.
While the PinePhone's modem does support all LTE bands that T-Mobile uses in the US (And is one of the best choices for band support with the PinePhone's modem in the US), VoLTE is still listed as "Under development" by the modem manufacturer. T-Mobile's system also does not list the PinePhone as a compatible device due to this lack of official VoLTE support. The modem is capable of working on T-Mobile with VoLTE support enabled.
According to this page, Verizon's primary frequency band for the United States is 13 (700 MHz).
Verizon's bands and protocols are summarized on this page. Verizon officially says:
Some Verizon users have had calls and and text stop working after around 2 weeks of use. This can be resolved by contacting Verizon support.
This carrier only accepts approved devices on its network. Even if a device supports some or all of the required frequencies for this carrier, it will not be able to connect unless the device is approved for this network. Check with the network operator to confirm whether a device is approved or not.
But the truth is that with any Verizon-Approved burner phone, you can activate a Verizon SIM and swap it into your PinePhone. Verizon does not care about what IMEI your phone has at all once the SIM itself is activated. 
According to this page, Telstra uses the LTE B1, B3 and B28 variants, which are all supported by the EG25-G modem.
Out of box: Supports 2G, 3G, 4G, Calls (in&out), SMS (in&out) work. Data not yet tested. Correct APN suggestions. Identifies as EMV (Manjaro Phosh CE)
Out of box: Supports 2G only (and is unstable), Calls (in&out), SMS (in&out) work. Data not yet tested. Correct APN suggestions.
Out of box: Supports 2G, 3G, 4G, Calls (in&out), SMS (in&out) work. Data (4G) tested and works with correct APN settings. Carrier details: https://sk.wikipedia.org/wiki/4ka
- The FrequencyCheck model page does not list either Pine64 or the PinePhone.
- T-Mobile's system does not list the PinePhone as a compatible device due to the lack of official VoLTE support from the manufacturer, despite the fact that it does work.
- MMS doesn't currently work in any distribution on the PinePhone by default. This means images and group chats will not work in text messages.
- Some providers may allow only certain known devices identified by their Type Allocation Code.