Can I Use my Sprint iPhone 4s with Straight Talk Wireless?

A reader, FatherFisher, asks

I have just upgraded to an iPhone 5S with Sprint. I want to give my old 4S to my son, who is on StraightTalk. When I check the IMEI on their website, they only accept ATT and TMobile 4S phones (or unlocked ones).
So I asked Sprint if they could unlock my phone. After being told the International Dept. does the unlock, they then told me it’s only for use outside the USA. Since my account is in good standing, they did give me the MSL (Master Security Lock??) code, but told me they have no idea how or where to use it.

Is there any way for me to get a CDMA Sprint 4S over to Straight Talk. I have spoken to them and they seem to have no idea — they just want me to buy the CDMA kit and give it a try, which I’d rather not do. OR is there any way to unlock the phone, now that I have the MSL code?


Hi FatherFisher,

This can get a little complicated.  Your Sprint iPhone 4s is both a Sprint CDMA phone and a SIM locked GSM phone. Let me try to explain.

Your Sprint iPhone 4s may be eligible to use on Straight Talk’s sprint compatible network.  Look up the MEID in your iPhone’s settings. Check Settings-General->About. Go to the Straight Talk CMDA BYOP page and enter your zip code and MEID and see if the phone is eligible.

If the phone is eligible, you can register and activate it. You’ll need to buy a Network Access Code at that point. Your son would want to add the phone to his Straight Talk account and transfer his service to it.

The web site should tell you if the phone isn’t eligible. Unfortunately, there isn’t a list of what makes a phone eligible. They might not use the Sprint network in your zip code. They may not want to register your model phone. Rumor is they aren’t allowed to activate Verizon and Sprint iPhone 5 models at this time.  They may be also checking the MEID of your specific phone to see if it is bad, meaning they won’t register it. Bad usually means reported lost or stolen.

Your iPhone 4s also has a SIM slot. But you can’t use it on Straight Talk without an 3rd Party unlock. Sprint SIM locks their iPhone 4s phones. They will not unlock them for domestic use.  They will unlock them for international use. This means if you could use the phone overseas but not here in the USA. And that is really too bad, it’s your phone, if you completed your contract, then you should be able to use it on whatever network you like.

If your son is using a Straight Talk phone with a micro SIM, or you can borrow a micro SIM  from someone, you can complete your unlock. The phone should prompt for the MSL. My guess is at that point, it will unlock and display a message that you can’t use the domestic SIM.

Finally, there are these 3rd party unlocks that can be used to trick the phone into using a SIM. Some readers told me they use the.  Search eBay or Google for sprint iPhone 4s unlock or sprint GPP and you can find more information. While these work, they have limitations. You can’t also update to the latest version of iOS.  These unlocks need to be tested and updated for new versions of iOS. And they cost another $10 – $20 dollars.

If you really can’t use this phone with Straight Talk, I’d sell it and buy a used ATT or Verizon iPhone 4s that you can use. You might be able to break even on the deal or it costs you a few bucks out of pocket. You don’t then need to live with the limitations of the unlock.

Let me know if you have more questions or how you make out. You might also wan to figure out if your son is currently using Straight Talk’s att, tmobile,verizon or sprint network. If it working well for him. He may want to stay on the network.



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