How to Activate an AT&T SIM Card Under an Existing Account

By Ashley Leonard

AT&T is one of the most popular cell phone carriers in the nation. They provide some of the most technologically advanced devices, such as the iPhone. In order for an AT&T cell phone to function, a SIM card needs to be installed. The SIM card holds the phone's information such as contact numbers and addresses. If you have an existing account with AT&T, it is possible to purchase and activate a new SIM card.

Things You'll Need

  • An AT&T cell phone
  • SIM Card

Activating a AT&T SIM Card

Step 1

Purchase a 3G SIM card from AT&T or any online retailer offering them. An AT&T SIM card costs from $5.50 to $12. Only existing account holders can buy a separate SIM card.

Step 2

Go to an AT&T retail store or speak with an AT&T representative to activate the SIM card. The representative will activate the SIM card either in-person or by phone by using your existing account information. Most likely there will be a fee to activate the SIM card.

Step 3

Place the new SIM card into your phone and turn your phone on. The SIM card should be functioning properly.

References & Resources