Learn how to increase the security of your iPhone’s physical SIM or eSIM by adding a numeric PIN. We will also show you what to do if you do not know the default SIM PIN or have exhausted the limit, which now requires you to enter a PUK code.
What happens after you add the SIM PIN
Find My iPhone is a great way to secure your iPhone in case it is lost or stolen, but it doesn’t do much to protect your physical SIM card. Without a PIN enabled on your SIM, anyone with access to your SIM card can use it to make phone calls, send messages, and use cellular data.
This is, of course, a worst-case scenario that I am describing here, but securing your SIM card with a Personal Identification Number (PIN) is a great way to add another level of security to your phone and make sure that even if the device itself becomes compromised, your cellular plan can remain protected.
Important: SIM PIN is set on the SIM card itself. So, even if you set the SIM PIN using your iPhone, you will have to enter the PIN if you insert this SIM card in other phones, be it an Android phone or a dumb feature phone.
Be very careful not to forget that SIM PIN, though, or your SIM card will be locked, and you will have to get in touch with your carrier to obtain a PUK code in order to unlock the locked SIM card.
Know the default SIM PIN
When you get a new SIM card, the SIM PIN is turned off, but most SIM cards have a default SIM PIN that you may be required to enter when you go to set the PIN for the first time.
In most cases, the default SIM PIN is 1234 or 0000. But you must always check your cellular provider’s website or ask customer care for the default SIM PIN. You may also ask the SIM card dealer for this information or look at the physical SIM card package or documentation.
Set a SIM PIN on your iPhone
1) Open the Settings app and tap Cellular, Mobile Data, or Mobile Service.
2) Tap SIM PIN. If you use two or more lines on your iPhone, select your physical SIM card or eSIM and then tap SIM PIN from the next screen.
3) Turn on the switch for SIM PIN. After that:
- If this is your first time setting up a SIM PIN, you will be required to create a new PIN containing 4 to 8 numbers. However, SIM cards from many carriers need you to enter the default SIM PIN, in which case this screen will say, “Enter PIN to lock SIM. 10 attempts remaining” or “Current PIN.” So, enter the correct default PIN.
- If you previously had a PIN enabled on this SIM card (irrespective of whether you did that on an iPhone, an Android phone, or a non-smartphone), you will have to re-enter that PIN to enable SIM protection.
4) Tap Done to enable SIM PIN.
Turn off the SIM PIN
- Open iPhone Settings and tap Cellular.
- Tap SIM PIN or select one of your lines and then tap SIM PIN from the next screen.
- Turn off the switch next to SIM PIN.
- Enter your current PIN in order to validate your request, and tap Done.
Get your PUK number if you forget your SIM PIN
After you enter your SIM PIN incorrectly a few times (usually, you get three to ten tries), the SIM gets locked out. You must then enter the Personal Unlocking Key (PUK) code. If you enter the PUK code incorrectly a few times (usually, you have ten tries), then that SIM card becomes useless, and you will have to get a new one from your carrier. In almost all cases, your carrier will be able to give you another physical SIM card or eSIM with the same old phone number.
I’ve saved the PUK code of my SIM cards in a locked note. My carrier shows the PUK code inside its official mobile app. But your mileage may vary. You should contact your SIM provider’s customer care via call, email, text, or chatbot to get the PUK code.
Note that you cannot change the PUK code, and it will stay the same for your SIM card even if you change your SIM PIN.
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