Although T-Mobile USA doesn’t directly offer the iPhone 4S like AT&T, Sprint, and Verizon, you can buy an unlocked iPhone 4S from Apple and use it on T-Mobile US network without too much problems. By using the iPhone 4S on T-Mobile you won’t lose any of iPhone 4S major features such Siri or FaceTime. The iPhone 4S on T-Mobile can still send MMS and use T-Mobile’s data. But the settings needs to be set up yet. Since the iPhone 4S uses micro sim card, you’ll need a micro SIM.

T-Mobile Micro SIM Card for iPhone 4S

Like the iPhone 4, the iPhone 4S uses a micro SIM card. T-Mobile has Micro SIM. T-Mobile’s currently giving micro SIM cards for free if you order it online. You can also buy one from your local T-Mobile store for $9.99. Now you can activate the Micro SIM card at any T-Mobile store or by calling T-Mobile.

Internet Data and pictures messaging iPhone 4S on T-Mobile

After your put the SIM card into the phone, you can make and receive calls without doing nothing else, as long you getting signal. But for data and MMS, if is not working, you’ll need to manually type the configurations needed in order to work. To begin, turn off the WiFi on the device first.

1. Then go to Settings > General and select Network.

2. Chose Cellular Data Network, and put the following information under Cellular Data:

  • APNepc.tmobile.com; if that doesn’t work use wap.voicestream.com
  • Username: Leave Blank
  • Password: Leave Blank
3. Under the MMS section, put configurations:
  • APN:  epc.tmobile.com
  • Username: Leave Blank
  • Password: Leave Blank
  • MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc
  • MMS Proxy: 216.155.165.50:8080  (Leave Blank for 4S)
  • MMS Max Message Size: 1048576  (Leave Blank for 4S)
  • MMS UA Prof URL: http://www.apple.com/mms/uaprof.rdf

4. Press the Network button to go back and press the home button to exit and save the settings.

5. Turn the iPhone off and turn it back on. Open up Safari and send a MMS message to check if everything is working.

If everything was done correctly, you should be receiving EDGE (2G) data speed, in mot cities. But if you’re lucky enough to be in cities like Alabama, Georgia, Nevada, California, Oregon, and Washington your iPhone 4S will receive full 3G services from T-Mobile.

To get FaceTime working on your unlocked T-Mobile iPhone 4S, you’ll first need to jailbreak it and then install MiTime from Cydia.

Siri on T-Mobile works very well if you can get a decent EDGE speed from T-Mobile. You can use Siri on T-Mobile’s data if you have a data plan but it will be slower than on WiFi or a 3G connection.