"unlocked" US phone will work in Mexico?

[panque]

Hello, after my X8 was stolen I was thinking of grabbing an unlocked phone from the US since they're cheaper there and using it in Mexico. Should work because it's unlocked right?

Newegg.com - Sony Ericsson Xperia Arc S Silver 3G Unlocked GSM Android Smart Phone w/ Android OS v2.3 / 4.2" Touch Screen / 8.1MP Camera (LT18a)

It worries me a bit that in the details tab it says "AT&T 3G Only". So would I be unable to use 3G data because I won't have AT&T ?

Is there something in the hardware that prevents the phone from doing so? or something in software?
Also, is unlocked the same thing as rooted?

thanks for the replies.

 

[Josh-SonyXperia]

You just need to make sure that the phone company that you want to use it with in Mexico support these 3G frequencies > UMTS 800 / 850 / 1900 / 2100 MHz

Unlocked means that you can use any SIM card from any company so it is not the same as rooted.

 

[panque]

Than you.