Is there an iPhone 6 model that works with both Verizon and ATT?

Not as you purchase it. It comes locked to the carrier you chose. The price you pay is based on a two year contract. The provider will not unlock the phone for you until that contract expires.

The 5S and 5C do either CDMA or GSM. I would presume that will be true of the new models. So it would then be possible to use the phone on either type of network with the proper SIM and having it fully unlocked from the previous carrier. But understand I am making an assumption only based on the 5S and 5C. Now some carriers can lock you to their service but not unlock you. I discovered this with Virgin Mobile, for example. I purchased an unlocked 5C that is now permanently locked to Virgin Mobile. It apparently cannot be unlocked for use on a different carrier.

Even though a phone can be unlocked does not mean the carrier is either willing or able to unlock it.

The Verizon iPhone is unlocked for all GSM carriers, but may not give LTE on all of them.

<https://www.apple.com/iphone/LTE/>

The AT&T iPhone, even when unlocked, won't work on Verizon because Verizon accepts only Verizon phones.

See the LTE chart. LTE will work for Verizon and AT&T, but some carriers in some countries may be limited to 3G.

Do you know if the unlocked contract free T-Mobile iPhone 6 will work on ATT?

If you get T-Mobile to unlock it.

<http://support.t-mobile.com/docs/DOC-1588>

Hi Bob,

The short answer is yes. I think the Verizon phone is the one you want.

The actual hardware for the AT&T and Verizon iPhones are identical. If you look at the specs for both phones you will see a whole list of wireless standards (GSM, CDMA, LTE) and frequencies (or "bands"). The iPhone 6 is packed with support for enough standards and bands to work on both networks, but (and this is a big but) the CDMA capability will only be turned on if you activate the phone with Verizon. It will also be locked to Verizon (and no matter what you won't be able to unlock it from Verizon). The good news is that AT&T doesn't use CDMA, it uses GSM. The even better news is that Verizon does not lock the GSM or LTE service (this is what the SIM card is for) and you can actually use a Verizon iPhone on the AT&T network out of the box.

So in summary:

Buy Verizon iPhone 6 --> CDMA locked to Verizon --> Any SIM card will work on day one.

Buy AT&T iPhone 6 --> CDMA disabled --> 2 years on AT&T --> AT&T unlocks phone, can use any SIM card you want -X-> still won't work on Verizon CDMA

Some of the details about what the bands and standards are for are here:

http://www.extremetech.com/extreme/189786-iphone-6-and-iphone-6-plus-complete-gl obal-cell-coverage-with-best-in-class-lte-and-wireless-connectivity

Maybe in a several years Verizon will dump CDMA and rely more on its LTE network (kind of like what happened a few years back when everyone went digital and dumped analog) and you can go from AT&T to Verizon. But I don't think that will happen for quite a while (certainly not in the next two years).

Best of luck!

Everyone is reporting that its UNLOCKED and will work on ATT....

No, they aren't. It's contract free. It's not unlocked until T-Mobile unlocks it.

"Everyone is reporting that its UNLOCKED and will work on ATT...."

How about a little clarification. Who is "everyone"? And what is "its"? Are you referring to the T-Mobile iPhone 6 or the Verizon iPhone 6? Or a previous version of the iPhone.

I was REPLYING to Bob NYC. I do believe it says that on my response. All the forums are reporting that the TMobile device with no contract IS UNLOCKED and will accept ATT sim cards. This was exactly the same procedure as the IPHONE 5S last year. Please consult the other forums. I don't think Tmobile and Verizon are compatible Im not sure..ive only ever been on ATT

The TMobile, ATT, and Verizon phones are the same hardware. This is new for the iphone 6. Older models had different LTE bands. There is a second iphone 6. I think Sprint uses that one but it's biggest difference is it's support for the unique standards in China.