5 Replies Latest reply: Dec 29, 2011 9:05 PM by dabbler RSS

How do I unlock the SIM card if I don't know the PIN?

I pulled my SIM card out to show someone what a SIM card was and when I put it back in found that I did not have cell/data reception and the time was wrong. Looking at the security settings revealed that the SIM card was locked and I need a PIN to unlock it.


I don't remember ever setting up a PIN. I tried all the things I would have likely used as well as the last 4 of my SSN, 1234, 0000, 000000 and everytime it says "Unable to change SIM card lock state. Possibly incorrect PIN."


Please help!




  • 1. Re: How do I unlock the SIM card if I don't know the PIN?

    You need to call Tmobile CS or live chatand they can give you

    the code.



  • 2. Re: How do I unlock the SIM card if I don't know the PIN?

    Gramps is correct.  We would be glad to assist, just remember that enough incorrect unlock attempts can permanently damage a SIM card.



  • 3. Re: How do I unlock the SIM card if I don't know the PIN?

    This reminds me my own situation. After I got my new phone recently, in a T-Mo store I had my old SIM card's data copied to the new phone's SIM card in order to transfer all my contacts and be able to use WiFi calling. Then later I decided to also secure the new SIM card with a PIN, figuring that there was no PIN number in it before. However, entering a new PIN number was rejected twice in a row, with reminders that I only had 2, then 1 attempt left before the SIM card becomes inaccessible. So, to be safe, I stopped further attempts before the 3rd one but still wondering how to proceed with this without failing the 3rd time. Once I asked a T-Mo store rep about this and he said that they would have to clone my SIM to a new one where I could then set my PIN number. This may be true but I'd rather keep the SIM card that came with the phone and I think I've read it in some T-Mo doc that they can provide an unlock code in case I fail with the PIN the 3rd time. So what is the right solution in my case here and why was that new SIM card acting like there was an old PIN in it in the first place?

  • 4. Re: How do I unlock the SIM card if I don't know the PIN?

    Thank you! I tried using the live chat. The rep was very helpful but ultimately it was not successful and they told me I will need to go into a t-mobile store and get a new one. They said mine was pretty outdated and their reset codes wouldn't work. Thanks.

  • 5. Re: How do I unlock the SIM card if I don't know the PIN?

    I finally got a resolution to my SIM PIN issue at another T-Mobile store. But it wan't easy. The rep I talked to told me to go ahead and guess the SIM PIN the third (and last) time and if I guessed wrong and the SIM card gets locked, he would get a PUK code to unlock it. Well, I guessed wrong again but he could not figure out how to get the PUK code and suggested to clone the SIM card to a new one. After he did that, I tried to set a SIM PIN code on that one but ended up the same way as with the first SIM card: I failed and had only two tries left. The rep then used up those two tries to no avail. I suggested that perhaps the SIM cards come with some default PINs, such as 0000 or 1234, because I remembered my old Moto phone's SIM card worked that way, but the Moto docs at least documented it. But it was now too late to try it on this phone. So the rep did a more thorough search in some internal documents till he finally did find the PUK code that worked on that SIM card. He also discovered that the SIM card had an initial default PIN code of 1234. With that I was then able to change it to my own PIN number. This whole thing could have been avoided if the Amaze 4G user manual mentioned the default PIN code in the first place, but all I could find in the manual is something like this:


    "Your SIM card is preset with a PIN (personal identification number) that is set by

    T-Mobile. If you’re asked for a PIN, enter it and then tap OK. If you enter the wrong

    PIN three times, your SIM card is blocked. Don't worry. Just contact T-Mobile and

    ask for the PUK (PIN Unblocking Key)."


    Nobody told me that T-Mobile preset the SIM PIN to 1234 and I suspect it's really the HTC factory default code, not of T-Mobile's. I just hope the new SIM card still has all the functionality of the card that came with the phone, including the Wi-Fi calling. I also hope that T-Mo gives more training about this to its store staff because they seem to be pretty ignorant about it.