Can I use my Iphone 4G outside US on any GSM carrier?

all iphones purchased in the usa are locked to at&t all of them no exceptions

The store manager said it can be used outside US on any GSM carrier.

That's correct. The phone will work only with AT&T SIMs, but will work in roaming mode with other carriers. You will be charged roaming fees on your AT&T account. For data, those charges will be exorbitant.

All iphone bought in U.S are carrier locked. Neither Apple Nor AT&T unlocks them and it can not be unlocked officially. So you will probably have to return it and get your money back (if within 30 days), if it's after 30 days return period, sell it and either buy one from the apple online in Canada. But you must have an active billing/shipping address in Canada. So if you have friends or relative that lives in Canada have them order one for you and have them ship to you.

gsiblini wrote:
I am in NYC and bought an Iphone 4G with part#MC318LL/A from an electronics store on 34rth Str. The store manager said it can be used outside US on any GSM carrier ; however it says on the box at&t and in settings :Carrier :ATT . I suspect that this is probably a locked phone .
Question: How to tell it is a locked phone or Not before I travel overseas?

Really? You bought your phone from an electronics store? Are they even authorized to sell the iPhone? I believe in the US, only Apple, AT&T, Walmart, Best Buy and Radio Shack are authorized to sell the iPhone. And just an FYI, while it is semantic, you didn't buy a 4G. You bought an iPhone 4.

Message was edited by: rbrylawski

You could use it on other carriers outside the US and even Tmobile here in the US but EDGE only (cannot be discussed here). You would need to make sure you have a roaming plan with AT&T to avoid huge international data chargers. Otherwise there is another way but such things are not allowed to be discussed at this venue. You should search else where for further information.

Message was edited by: Randy Fast

He bought a hacked phone from an unauthorized source.

If I were you, I'd return the phone for a refund. You've bought a hacked phone rather than a legitimately unlocked phone. As long as you NEVER update or restore the phone, it will work.