How to Add an Existing Phone to Your AT&T Plan

by Kenyonda Bradley

There may come a time when you will need to add an existing phone to your AT&T account. This may occur in the event that you want to swap out a phone or add another line to your services. Whatever the reason may be, adding an existing phone to your AT&T plan is easy to accomplish.

Step 1

Contact AT&T customer service department at 1-800-331-0500. Follow the prompts to speak with a representative.

Step 2

Provide the representative with your account number, name and account pass code when prompted.

Step 3

Inform the representative that you would like to add an existing phone to your account. If the phone is registered to AT&T and you are swapping out the device, you will need to provide the representative with the phone's ESN or HEX number. The ESN or HEX number is located on a sticker inside the battery compartment. If you are adding an existing phone line to your account, inform the representative that you would like to upgrade your account to add an additional line of service. If you have an individual plan, you will need to upgrade to a shared plan. Provide the representative with the ESN or HEX number of the AT&T phone that you would like to add to the account.

Follow the instructions provided by the representative to activate the phone. Wait until the activation is completed, and restart your phone if told to do so.


  • If you want to add a non-AT&T phone to your account, you must have the device unlocked from its previous network before you can add on your plan.
  • You may be charged an activation fee to add an existing phone to your plan.


About the Author

Based in Chicago, Kenyonda Bradley has been writing for online publications since 2008. With more than 10 years of experience as a hairstylist, she is also studying to become an elementary school teacher.

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