Would there be any problem using a locked AT&T S3 on Simple Mobile?

[swhite237]

One of my friends wants to buy an S3 off of me and use it on Simple Mobile, but for some reason he doesn't want me to unlock the phone. Would there be any problems putting a Simple Mobile SIM in the S3? It isn't on contract. I know I would need to change the APN for data to work, is there going to be any problem changing the APN on a locked device?

 

[trwrt]

I haven't tried it myself, but I'd guess it's very unlikely this would work. Simple Mobile uses the T-Mobile network and I doubt that an AT&T locked phone would operate on it, whether you change the APN or not. I've used an AT&T locked phone on Straight Talk but that was with a SIM for their AT&T network MVNO, if I'd had the SIM for their T-Mobile network setup I don't think it would have worked. But, I could be wrong, maybe someone will respond who has actually tried it.

I think if you put the SIM in and boot it up you will find out right away, it should come up and ask you to enter an unlock code when it sees a non-AT&T SIM if I remember right.