SIM card locked? How to enter the PUK code and get your phone working again

Three wrong PIN guesses lock the SIM until you enter a PUK code. You can get it from your carrier, but you must be careful, because ten wrong PUK tries ruin the SIM.

Agha Ali Abbas3 October 20265 min read

A phone that suddenly says SIM Locked, Enter PUK or SIM PIN is not broken. It is doing what it was set up to do. The SIM has a security PIN, three wrong entries blocked it and now it needs a longer unlock code from your carrier. The fix is simple, but one mistake can ruin the SIM, so go carefully. Below are the steps for iPhone and Android, how to find the PUK and what to do if the SIM is blocked.

PIN, PUK and phone passcode: what is the difference?

SIM PIN: a four to eight digit code that locks the SIM card itself. The phone asks for it when it restarts or when you put the SIM in another phone.
PUK: the PIN Unlock Key, usually eight digits. It resets the SIM PIN after too many wrong attempts.
Phone passcode: the code that unlocks your screen. It is unrelated to the SIM.
Account PIN: the carrier's code for customer service. It is not the SIM PIN either.

Step 1: make sure you really need the PUK

If the phone asks for a SIM PIN and you still have attempts left, try the PIN once more. If you never set a PIN, the carrier may have used a default. Carriers often use a default code, such as 1111, 0000 or 1234, but it differs, so check your carrier's help page before you guess. Be careful, since each wrong try counts. After three wrong attempts, the SIM is locked and asks for the PUK. Stop guessing at that point.

Step 2: get your PUK code

1
Check the SIM packaging.
The plastic card the SIM came in often has a scratch-off area with the PIN and PUK printed on it.
2
Ask your carrier.
Sign in to your carrier's app or website, or call customer service from another phone. They will verify your account and tell you the PUK for that SIM.
3
Say which SIM it is.
Give the phone number or the ICCID, the long number printed on the SIM. On a dual SIM phone, make sure it is the right line.
4
Write down the PUK.
Keep it ready, and check each digit before you type it.

Step 3: enter the PUK on your phone

The fix

iPhone

1
When you see SIM Locked or Enter PUK, tap the field and type the PUK.
2
Enter a new SIM PIN when asked.
Choose four to eight digits that you will remember, and confirm it.
3
Wait for the signal to return.
Your carrier name and bars should appear in a few seconds.

The fix

Android and Samsung

1
On the SIM unlock screen, enter the PUK code.
2
Enter and confirm a new PIN.
3
Restart the phone if the service does not return in a minute.

How to turn the SIM lock off (or on)

The SIM lock is a security feature. It stops a thief from putting your SIM in another phone and using your number. If you do not want it, you can turn it off, but you need the current PIN to do it. If you want the extra protection, leave it on and choose a PIN you will remember.

iPhone: go to Settings › Cellular › SIM PIN, and turn SIM PIN off or on. Enter the PIN to confirm. On a dual SIM iPhone, choose the line first. If you do not see this setting, your carrier may not support it.
Samsung: go to Settings › Security and privacy › More security settings › Set up SIM card lock, then toggle Lock SIM card. Menu names vary by version.
Pixel and other Android: go to Settings › Security & privacy › More security & privacy › Encryption & credentials or SIM lock, depending on your version, and toggle Lock SIM.

Why is my SIM asking for a PIN?

You, or someone else, turned on SIM PIN in settings.
You put the SIM in a new phone, which asks for the PIN to confirm.
The carrier shipped the SIM with a PIN lock turned on.
The phone restarted after an update or a crash, and SIM PIN asks after every restart.
Someone tried to use your SIM in another device, and it locked.

If you did not set it and you are not sure how it got locked, think about whether someone had access to your phone. Check your account for changes, and consider adding a carrier PIN. See how SIM swap scams work.

If the SIM is permanently blocked

1
Contact your carrier.
Use its app, website or a store with a photo ID. Explain that the SIM is blocked.
2
Ask for a replacement SIM or eSIM.
Carriers usually give a new SIM for free or a small fee. You keep your number.
3
Swap the SIM, and activate it.
See how to remove and replace a SIM card. Follow the carrier's activation steps.
4
Set a PIN you will remember, or leave the lock off.
Write the new PIN and PUK in a safe place.

Still no service after unlocking?

If the SIM is unlocked but the phone still has no signal, the cause is likely something else. Restart the phone, toggle Airplane Mode and check the carrier for outages and account status. See what to do when an iPhone has no service or what to do when a Samsung says not registered on the network.

Frequently asked questions

What is a PUK code?

PUK stands for PIN Unlock Key. It is a longer code, usually eight digits, that your carrier can give you to unlock a SIM after too many wrong PIN attempts.

How many tries do I get to enter the PUK?

Usually ten. After ten wrong tries, the SIM is permanently blocked and you need a replacement from your carrier.

Where do I find my PUK code?

Ask your carrier through its app, website or support line, or look on the plastic card your SIM came in, which may have it printed under a scratch-off. You may need to verify your account.

Why does my phone ask for a SIM PIN?

Someone, or a past you, turned on the SIM lock, or you bought a phone or SIM that had it enabled. The PIN asks for confirmation every time the phone restarts.

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