How to Make a Duplicate SIM Card for My AT&T Phone

By Erick Kristian

SIM cards carry all the associated data for that phone number.
i George Doyle & Ciaran Griffin/Stockbyte/Getty Images

Duplicating the SIM card for an AT&T phone can be done with the use of a SIM duplicator. A SIM duplicator is a device that copies one SIM card to another. SIM duplicators are inexpensive and available online and at cell phone equipment retailers. The process is relatively quick and does not require advanced technical knowledge. A duplicated SIM is handy in case the original SIM is lost or corrupted.

Step 1

Turn off the AT&T phone and remove the SIM card. The process for removing the SIM card varies by phone model.

Step 2

Locate the IMSI (International Mobile Subscriber Identifier) number. This number is usually found on the SIM card itself and is 14 to 16 digits.

Step 3

Insert the original SIM into the SIM card duplicator. The duplicator will locate the unique key (Ki) associated with the SIM card. This is unique to that SIM and required for duplication.

Step 4

Save the SIM profile to the duplicator. The process for doing this will vary by model.

Step 5

Remove the original SIM card and insert the blank SIM card.

Step 6

Copy the data from the original SIM card to the blank one. This process will take seconds. The blank SIM card will now function exactly as the original one.