I know that several years ago, some iPhones had CDMA and others GSM, and others yet had both, depending on which carrier the phones were meant to work with.

But I read somewhere that nowadays, all of them come with extensive network compatibility. AT&T told me that their phones are locked but can be unlocked once fully paid off. So it sounds like there is a software lock but perhaps the hardware is universal.

I am looking to buy a T-Mobile phone, get it unlocked, and then switch immediately to using another carrier.

Are all iPhones the same now, in terms of communication hardware/software?

  • AT&T says I can unlock my phone after it is paid off. What good would it be to "unlock" a phone if it won't work with other carriers? Nov 8, 2017 at 21:33

2 Answers 2


No in 2017 and still no in 2023.

In 2023 with iPhone 15 pro, there are 4 models. Even in the US with no physical SIM, you can stil get carrier locked based on how you purchase the device. Many purchases are unlocked, especially non-subsidized purchases direct from Apple.

Use of an eSIM requires a carrier that supports eSIM and a wireless service plan (which may include restrictions on switching service providers and roaming, even after contract expiration). See your carrier for details. To learn more, visit https://apple.com/esim .

For detailed radio bands - consult the article 5G and LTE. Find the iPhone that’s right for your country or region.

In the US, CDMA models can work on GSM but the other way, not so much.

Worse, in the US, Sprint and Verizon are not willing to bring aboard a device from the other carrier despite CDMA and GSM potentially being technically compatible.

The GSM phones when unlocked work across pretty much any GSM carrier. The CDMA phones when unlocked also work across pretty much any GSM carrier or the specific carrier that the device was assigned to initially. (So I would generally be able to bring a Verizon iPhone from another person to my Verizon account)

  • 1
    Can you cite any recent sources. I can't find it at the moment, but I recently read an article from perhaps 1 year ago that was saying that all iPhones are now potentially unlockable. AT&T told me they would unlock theirs although I guess they are GSM so maybe that is normal. Nov 3, 2017 at 22:34
  • Yes. I’ve updated the answer @ButtleButkus
    – bmike
    Oct 18, 2023 at 23:20
  • it seems like most major U.S. carriers support eSim and eSim transfers. So, I suppose if you buy direct from Apple now you can probably use most US carriers. support.apple.com/en-us/HT209096 ... And I see that AT&T has a procedure for unlocking (though I can't speak to any problems that might arise): att.com/support/article/wireless/KM1262649 Oct 19, 2023 at 0:16
  • You are correct @ButtleButkus all carriers do have an unlock procedure and sometimes people don’t like the hoops or terms they need to fulfill to get an unlock.
    – bmike
    Oct 19, 2023 at 1:16

You are correct, there is no longer a distinction between iPhones sold by different U.S. phone carriers. While some carriers might impose “carrier locks” depending on the terms of your service contract, all iPhones 6 and later are physically compatible on any network.

There are two reasons for this. For one, iPhones since the iPhone 6 started shipping with dual-band support, offering functionality for both CDMA and GSM networks. A second, more recent, development is that in 2022, U.S. phone carriers shut down their old 2G and 3G networks, transitioning fully to 4G LTE for voice calling and 4G LTE or 5G for cellular data. The difference between CDMA and GSM phones was rooted in how they communicated across 2G and 3G bands, and now that the older 2G and 3G bands are no longer in use, there is no longer a need for separate CDMA and GSM devices.

Source: CDMA vs. GSM: What's the Difference?

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