How to get 3G/4G on Galaxy S3 moved to different carrier?

[AC Question]

I've got a Samsung Galaxy S3 which was originally on Verizon. I was tired of paying the bill with them, so I got my phone unlocked by a phone kiosk place, so I could be moved onto Simple Mobile (T-Mobile network). The call and text works fine, but I can't send picture messages, and more importantly, my data speed is AWFUL. For some reason I didn't quite understand, I can't get 3G or 4G data on my phone now. I was wondering now that my phone is unlocked, can I move to a different carrier that will allow my S3 to get 3G/4G data? I was looking at Straight Talk, but not sure, and it appears Virgin mobile does not allow you to bring a phone over?

 

[Golfdriver97]

Welcome to the forums.
Check this thread out: http://forums.androidcentral.com/samsung-galaxy-s3/402892-verizon-unlocked-t-mobile.html

 

[RumoredNow]

I've got a Samsung Galaxy S3 which was originally on Verizon. I was tired of paying the bill with them, so I got my phone unlocked by a phone kiosk place, so I could be moved onto Simple Mobile (T-Mobile network). The call and text works fine, but I can't send picture messages, and more importantly, my data speed is AWFUL. For some reason I didn't quite understand, I can't get 3G or 4G data on my phone now. I was wondering now that my phone is unlocked, can I move to a different carrier that will allow my S3 to get 3G/4G data? I was looking at Straight Talk, but not sure, and it appears Virgin mobile does not allow you to bring a phone over?

The root issue is the radio. Branded phones can get pretty specific as to which frequencies they can use. Carriers like it this way as it keeps you tied to their network.

Your S3 variant has the following frequencies:
2G (EDGE): 800 / 1900 - - - This is probably all that Simple can communicate with if it is reselling T-Mo - - - This is your only GSM (SIM card based) radio and it is only really meant for International travel.
3G: CDMA2000 1xEV-DO - - - This is straight up 3G (no H+ or "faux G" or 3.5G) and is a pretty common spectrum.
4G: LTE 700 MHz Class 13 - - - This is what hurts you the most. Verizon is the only major carrier in the US using class 13 LTE. There are a few rural carriers piggybacking on this spectrum, but throw them out...

You are probably going to be limited to 3G 1xEV-DO no matter where you go, unless it is back to Verizon.

Resellers that will allow you to Bring Your Own Device are usually talking about SIM card activation and that means EDGE speed for your phone. One reseller that allows Verizon branded phones (and runs on Verizon towers) is Page Plus and you would get 3G - but no LTE that I know of.

If you can't afford a new phone, try Page Plus. If you can afford a new phone, get the Nexus 5 and take it to almost any 3rd party reseller and get up to LTE depending on the plan/carrier. A Nexus 5 would do well on Straight Talk as they now offer LTE.

Here's your phone spec: Samsung Galaxy S3 CDMA - Full phone specifications
Here's Carrier Frequencies: Mobile country code - Wikipedia, the free encyclopedia
Here's LTE Networks: List of LTE networks - Wikipedia, the free encyclopedia