Want to make sure no one can use your SIM if your iPhone gets lost or stolen? Changing the default SIM card PIN is a smart move — and it only takes a minute.
Most carriers use easy-to-guess default PINs like “1234” or “0000.” Here’s how to replace that with something more secure.
Why You Should Change Your SIM PIN
Your SIM PIN is like a password for your SIM card. If someone removes your SIM and puts it in another phone, they won’t be able to access your cellular service without the correct PIN.
But here’s the problem: most carriers use default PINs that are publicly known. That’s why setting your own custom PIN is a simple way to add extra protection to your account.
Step 1: Enable the SIM PIN Setting
If it’s not already turned on, start here:
- Open Settings.
- Tap Cellular (or Mobile Data in some regions).
- Select SIM PIN.
- Toggle SIM PIN ON.
- Enter your current PIN (usually the default from your carrier) to confirm.
Not sure what your current SIM PIN is? Try your carrier’s default, or contact them to get it.
Step 2: Tap “Change PIN”
Once SIM PIN is enabled:
- Tap Change PIN.
- Enter your current PIN again to proceed.
This confirms you’re authorized to make the change.
Step 3: Set a New Custom SIM PIN
Now set your new code:
- Type in your new 4-digit PIN.
- Tap Done.
- Re-enter the new PIN to confirm and tap Done again.
That’s it — your SIM is now protected with a new, private PIN.
Forgot Your SIM PIN? Don’t Guess
Entering the wrong SIM PIN too many times will lock your SIM, and you’ll need a PUK code from your carrier to unlock it. Never try to guess!
If you forgot the PIN:
- Contact your carrier and ask for the PUK code.
- Enter the PUK correctly to unlock your SIM.
- Then, you can set a new PIN from scratch.
Quick SIM PIN Tips
- Pick a code you won’t forget — birthdays or important dates are good.
- Avoid obvious numbers like 1234 or repeated digits.
- Write it down somewhere safe if you’re worried you’ll forget it.
- You can always turn off SIM PIN temporarily if needed (but turn it back on after).