How to Copy Contacts From a G1 to a SIM

1. Open the Android Market app and search for Contact2Sim. As of October 2010, there are two results for that search, a basic version that allows you to copy all of your contacts to your SIM card, and another version called Contact2Sim Pro that gives you the ability to copy individual contacts instead of your entire contact list. As of October, 2010, Contact2Sim Pro costs $5.50 to download, while the basic version is free. Both versions will give you the desired result. Install whichever version best suits your needs.

2. Navigate to the installed app on your phone and open it. There will be two tabs at the top, one labeled 'T-Mobile G1' (or whatever model phone you are using) and the other will say 'SIM card (x),' with the (x) representing the number of contacts stored on that SIM card. By default, there will be a handful of phone numbers already on the SIM card, all relating to T-Mobile services. Select the tab on the left, the one labeled with your phone's model.

3. Press the 'Menu' button on your phone to access the app options. Select the button labeled 'Copy missing to SIM.' A confirmation window will appear, telling you the number of contacts that will be copied. Press 'OK' to continue. Contact2Sim will begin transferring your stored contacts to the SIM card, a process whose duration will depend on the number of contacts you are transferring. When finished, a second window will appear to inform you of a successful transfer.

4. Reversing the process is very simple. Select the tab on the right, labeled 'SIM card (x).' Press the 'Menu' button on your phone, and select 'Copy missing to T-Mobile G1.' The app will transfer all contacts from the SIM card to your phone, excluding those that are already saved to the phone. You also have the option of erasing your SIM card while in the 'SIM card' tab.