How to Activate an AT&T SIM Card

This minHour teaches you how to activate a brand new AT&T Wireless SIM card on AT&T's website.


Locate and/or write down your IMEI number.

This is a special code connected to your phone, typically printed and clearly labeled on the packaging. If you don’t have access to this number, you can get it by dialing *#06# on the phone’s keypad.

Locate and/or write down your SIM card number.

This is also known as an ICCID number and is printed on the SIM card next to “ICCID.”

  • If you don’t see “ICCID,” it may be printed next to “CSN” or “EID.”

Turn off your phone or tablet.

If you’ve already inserted the new SIM into your device, you can skip to step 6.

Transfer a phone number from another provider (optional).

If you’re not transferring a phone number from another mobile provider (e.g., Verizon, T-Mobile), skip to step 3. If you are transferring a phone number, follow these steps to complete the transfer before you continue:

  • Go to in a browser.
  • Enter the phone number you want to transfer and the billing ZIP code.
  • Click Continue.
  • Provide the requested information and follow the on-screen instructions to activate your card.

Insert the SIM card.

If you’re not sure how to do this on your phone or tablet, visit AT&T’s Device Support site in a web browser. Once you’re there, select your model, click , and then click for instructions.

Turn on your phone and make a test call.

You should also try using the mobile internet service without Wi-Fi enabled. If you are able to do these things, your SIM card is active, and you can start setting up your voicemail. If not, continue with this method.

Go to

This opens the SIM card activation site.

Enter the SIM and IMEI numbers and click Continue.

The site will check your information and display instructions for your service and device.

Follow the on-screen instructions to activate the card.

Once the SIM is active, you’ll be able to place phone calls and use the internet.

  • If you’re unable to activate the card online, you can give AT&T a call from a working phone or visit an authorized AT&T store during regular business hours.
  • AT&T support is available 24/7. If you’re in the US, dial 1-800-331-0500. If you’re outside of the US, dial 1-314-925-6925.

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