Can i buy off contract AT&T phones and just switch SIM cards?

[KingGheedora]

I have an iphone right now, can I just buy another smartphone and put the SIM card into the new phone and it'll work?

Or do I need to get any new phone activated before it can be used? I'm getting the Captivate when it's out, and might start messing with it in terms of rooting and custom ROM's and stuff like that, and also might want to develop apps myself. If I do this I will want to have a backup phone in case my Captivate gets temporarily fucked from the tinkering.

Dataplan is not an issue since I already pay for the iphone dataplan, with unlimited data, and i'm not looking to do anything shady.

 

[Aikouka]

I'd imagine that it'd work. I used to switch SIM cards between phones when my old job did not allow camera phones in the office. Although, it wasn't the phones in question. Oddly enough, when I originally got my iPhone 3GS, I asked the lady at AT&T if something happened to my phone, could I put the SIM card into my old AT&T Tilt (HTC TyTn II)... she told me no. :hmm:

Although, if you have an iPhone 4, that uses a mini-SIM card, so you'd most likely need an adapter for another phone.

 

[Suspicious-Teach8788]

Can the Capitvate get custom ROMs? Samsung's not known for leaving their bootloaders easily unlocked although at least it doesn't have the annoying TI OMAP security features....

 

[Raduque]

Can the Capitvate get custom ROMs? Samsung's not known for leaving their bootloaders easily unlocked although at least it doesn't have the annoying TI OMAP security features....

Galaxy S phones are already rooted. The root method for the GalS works perfectly on the Captivate and Vibrant, according to various android sites.

As for the OP's question, yes, that's pretty much exactly how SIM cards are designed to work. You simply remove from one phone and install in another one. The only exception is, as Aikouka said, the iPhone4 and iPad, as they both use MicroSIMs and you'll need an adaptor to use it where a normal-sized SIM goes.

 

[KingGheedora]

Cool. Looks like the answer is yes, though with AT&T, they segment their dataplans according to phone type. I i move SIM from my new android to any iPhone, the voice will work but data will not. But if I move the SIM to any other android, both voice and phone would work.

 

[bassoprofundo]

I've had no problem swapping back and forth between a variety of phones for years now. However, iPhones (and Blackberries, btw) have specific data plans. That said, Blackberries are the only ones that HAVE to have a phone-specific data plan to function (because of the BIS interaction). An iphone can function with a non-iphone data plan, and other smartphones can function with an iphone data plan. The problem is that when AT&T does their periodic IMEI sweeps, they'll see if you're on a different data plan than is correct for your phone and switch you automatically if needed. This is especially true for the iphone if you're using a non-iphone plan. It has been my experience that if you are on an iphone plan and swap out to other phones periodically, no problem. However, if you're on a regular smartphone plan and swap to the iPhone for any length of time, they'll bug you to switch to an iPhone-specific plan. Everything should function okay with your current plan and SIM with the possible exception of voicemail issues due to the Captivate not having the same Visual Voicemail.