Guides / Set a SIM PIN

How to set a SIM PIN on iPhone

Updated 2 November 2026 · By the FirstHour team

Short answerOpen Settings, tap Cellular, then SIM PIN, and turn it on. Enter your carrier's default PIN if asked, then change it to your own. Don't guess the PIN, because wrong tries can lock the SIM for good.

Why it helps

Your SIM receives your login codes by text. Without a SIM PIN, someone could put your SIM in another phone and receive those codes. With one, the SIM locks after every restart or removal until the PIN is entered.

Before you start

Find your carrier's default SIM PIN first, on your SIM's packaging or by asking your carrier. Don't guess it. Apple warns that wrong guesses can lock your SIM permanently, and then you'd need a replacement.

Step by step

  1. Open Settings and tap Cellular. It's called Mobile Service or Mobile Data on some iPhones.
  2. If you have more than one line, choose the one you want to protect.
  3. Tap SIM PIN and turn it on.
  4. Enter the PIN. If you've never set one, use your carrier's default.
  5. Tap Done.
  6. Tap Change PIN, which appears once the switch is on, and choose your own. Write it down somewhere other than your phone.

What you'll notice

Every time your iPhone restarts, it asks for the SIM PIN, and until you enter it the status bar shows Locked SIM. That's the only change day to day.

If you forget it

  1. Contact the carrier that gave you the SIM or eSIM.
  2. Ask whether they can unlock it with the default PIN or a PUK code.
  3. If they can't, or your iPhone says PUK exhausted, you'll need a new SIM or eSIM.

How FirstHour helps

A SIM PIN is one of the guided tips in Plan B, with the steps laid out for you. FirstHour can't turn it on for you or check your PIN.

Questions

Does a SIM PIN work with eSIM?

Yes. Apple's steps cover both a SIM card and an eSIM.

Is a SIM PIN the same as my iPhone passcode?

No. Your passcode unlocks the iPhone. The SIM PIN locks the SIM itself, so don't use the same number for both.

Sources

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