How to Permanently Erase SIM Card Data

By Ben David

Subscriber Identification Modules, or SIM cards, are portable cards used to store personal identification information in GSM-based cellular phones. The information includes things like phone numbers, other phone book information, text messages and other model-related data. Service providers that operate on the GSM (Global System for Mobile Communication) network use SIM cards, and these can be transferred between different mobile phones on the same network with relative ease. The information stored on these cards can also deleted in the same manner, regardless of the type of phone in which they are used.

Step 1

Install the Sim Doctor application onto your computer. Sim Doctor is a free application for Windows PCs, and is available for download from

Step 2

Connect the card reader to the PC via the USB port, and insert the SIM card into the card reader. The program will launch and detect the card reader and the SIM card.

Step 3

Select “Speed Factor” in the Sim Doctor application window. The default setting of “Auto” will be pre-selected. This is the recommended setting for the card reading process.

Step 4

Click the “Start” button in the dialog window to start the card reading process. This process may take anywhere from 1.5 to 2.5 hours, depending on the speed chosen at set-up. Once the reading process is complete, another window displaying the SIM information will open.

Step 5

Click the “Format SIM” button in the information display dialog window. The process of formatting the disc will erase all of the old information on the SIM card and restore it to its original state.

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