Activating your AT&T phone or SIM card is quick and easy with the online AT&T activation portal. Simply insert your SIM, visit att.com/activate, enter your device details, and restart your phone to start using calls, texts, and data instantly. 

Step-by-Step Guide 

• Power off your device
  
  

• Insert the physical SIM or scan the QR code for eSIM
  
  

• Restart your phone
  
  

If your device shows “No SIM” or “Invalid SIM,” reinsert or check compatibility.

You will need:

• SIM Card Number (ICCID)
  
  

• Device IMEI
  
  

• AT&T Account or Order Number

• Sign in or create your AT&T account
  
  

• Enter the SIM/IMEI details
  
  

• Confirm your plan and number
  
  

• Submit and wait for confirmation

• After activation, restart your phone and enable Mobile Data.

• You should now see AT&T or 5G/LTE on your signal bar.

What’s Next?

• Voicemail & Call Forwarding
  
  

• AT&T Prepaid or Postpaid Plans
  
  

• 5G Settings and Hotspot

1. How long does AT&T activation take?
Activation usually takes 5–10 minutes, but in some cases, it may take up to an hour for network updates to complete.

2. Can I activate my AT&T SIM without an account?
No, you must sign in or create an AT&T account to activate your SIM and link it to a phone number or plan.

3. Why is my AT&T SIM not working after activation?
This may happen due to an inactive plan, device lock, or network issue. Restart the device or contact AT&T if the “No Service” message persists.

4. Do I need Wi-Fi to activate my AT&T phone?
Yes, it's recommended to use Wi-Fi or a stable internet connection during activation to complete setup and receive confirmation updates.