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Step 1
Choose the activation process that best suits your needs. You can activate your used cell phone online, in person (at an AT&T store or authorized dealer) or over the phone with a customer service representative.
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Step 2
Confirm that the cell phone is compatible with AT&T's network. In order to activate a used cell phone with AT&T, the phone must be a compatible GSM phone. When you contact AT&T, someone can verify if your phone is suitable for their network system.
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Step 3
Locate the phone's electronic serial number (ESN). The customer service representative uses the ESN to check the status of the phone and to verify whether or not there's a previous balance on the account and if it was reported lost or stolen. If the phone was reported lost or stolen, an AT&T representative must first speak with the person who reported it lost or stolen before you can activate the phone.
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Step 4
Select a plan and pay the required fee(s). Depending upon your credit history and choice of service plan, you may or may not have to pay a service activation fee and deposit. If you are asked to make a payment, you must do so before your phone is actually activated.
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Step 5
Finish the activation process. A customer service representative guides you through the entire activation process with just a few steps. You can use your phone immediately after the activation process is complete.








