Is Your iPhone GSM or CDMA? How to Tell
Wondering if your iPhone is GSM or CDMA? Recent iPhones, roughly since 2018, support both GSM and CDMA, so a modern iPhone is really neither one nor the other. It works on any major US carrier. So the real iPhone GSM or CDMA answer today is simple. The old split barely matters now.
That split used to decide which carriers your phone could join. Here is what changed, and how to check what your own iPhone supports.
What GSM and CDMA even mean
Both are old ways phones talked to cell towers for calls and texts.
In the US, AT&T and T Mobile ran on GSM. Verizon and the old Sprint ran on CDMA.
Years ago a CDMA phone often could not switch to a GSM carrier, so the label mattered when you bought or sold a phone.
Why it no longer matters much
Two big shifts made the old question mostly pointless.
First, recent iPhones include the radios for both systems in one phone. Apple stopped making separate GSM and CDMA models years ago.
Second, carriers have shut down their old CDMA and 3G networks. Verizon retired its CDMA network, and calls now run over newer LTE and 5G using a feature called VoLTE, short for Voice over LTE.
So today the real question is not GSM or CDMA. It is whether your iPhone is unlocked and supports VoLTE, which every iPhone from the last several years does.
How to check what your iPhone supports
You can see your model and its network details in a minute.
- Open the Settings app (the gray gear icon).
- Tap General.
- Tap About.
- Look at the Model Name line to see which iPhone you have.
- Scroll down to see network info like your carrier and Modem Firmware.
To confirm the model number, look at the Model Number line and match it on Apple’s identify your iPhone page, linked below.
How to tell if your iPhone is unlocked
Unlocked matters more than GSM or CDMA. An unlocked iPhone accepts a SIM or eSIM from any carrier.
- Open Settings, then tap General.
- Tap About.
- Find the Carrier Lock line.
- If it reads No SIM restrictions, your iPhone is unlocked and free to switch carriers.
If it names a carrier or says there are restrictions, contact that carrier to ask about unlocking.
Buying or selling a used iPhone
Since new iPhones handle both systems, focus on two things instead.
Check that it is unlocked, using the Carrier Lock step above. Then check that the model is sold in your country, since a phone built for another region may miss the bands your carrier uses.
Get those two right and the phone will work on AT&T, Verizon, or T Mobile without worrying about the old GSM or CDMA labels. It helps to know what factory unlocked really means before you buy.
Ready to make the move? Our guide on switching phones on T Mobile covers the eSIM steps, and if you carry a smartwatch too, here is whether Apple Watches are carrier locked.
People also ask
Is the iPhone GSM or CDMA? Modern iPhones are both. Since roughly the iPhone 8, a single model carries the radios for both systems, so it is not locked to one type.
Will an old Verizon iPhone work on AT&T? If it is unlocked and recent enough to support VoLTE, yes. Very old CDMA only iPhones may not, since the 3G networks they relied on are shut down.
Does CDMA still exist? Barely. US carriers have retired their CDMA networks, so phones now use LTE and 5G for calls and data.
How do I know if my iPhone has VoLTE? Go to Settings, Cellular, Cellular Data Options, and look for a Voice & Data or VoLTE option. If it is there, your iPhone supports it.