A friend gave me an ATT IPhone, can I use it on Verizon?

no, you can't

4s yes, anything older no.

not true, Slovette. An ATT locked iPhone, ANY model CANNOT be used on Verizon. Nor can the Verizon iPhone 4 or 4S be unlocked to be used on AT&T.

why what?

Don't know, contact Verizon and AT&T and ask them.

The iPhone 4S uses a transceiver made by Qualcomm that will work with either type of network as needed. But that is not the case with the iPhone 4, or any earlier versions. All AT&T iPhones, including the 4S, are locked to AT&T. If the phone finds any SIM card installed other than an AT&T SIM, it will disable the SIM, shutting off the phone and data features of the device, rendering it usable only through Wi-fi for data and voice (using an app like Skype). AT&T will not unlock the phone for you, even if you're under no contractual obligation with them.The only workarounds require "jailbreaking" (hacking, which can render it unstable or insecure) the phone or buying an unlock code from a third party (which is not guaranteed to work, and really pushes the boundaries of legality).

It is possible, lets not hide that fact. It's just not in parallel to Apple policy if you pursued it.

Nobody said it wasn't technically possible. They just said that was the policy of Verizon and AT&T (NOT Apple) not to allow it. And yes it is possible (although since there is no current effective hack under iOS 5.01 with the 4s they may have to wait awhile) but something that is a violation of the ToU, that you also agreed to, to discuss it here. It is not hiding the fact, just following the rules.

I have a 4S locked to AT&T. I just bought a H2O Wireless SIM on eBay for $.99 , activated it on their website, stuck it in the phone and it unlocked it to work on their network. Works great with the same coverage as AT&T and no contrct.

randyfromfriendswood wrote:

Can you switch an Att IPhone to Verizon?

The main reason you can't is that Verizon uses CDMA cell service where AT&T are a GSM cell service.

It's kinda like trying to run a Windows program on a Mac. They are 2 different services and the iPhone 4 does not have the dual 'chip' like the 4s does.

Thank you! thats the first answer that made sense on here.

What I would like to know is if there a workaround? a different chip..or? Would love to use the phone my son gave me but am not willing to switch to AT&T to do it.

No. There is no workaround other than buying a new phone.

As stated in your previous post there is no way to do this.