You can copy your contacts between your SIM and your tablet. This way, you won't lose your contacts if you change your SIM or tablet.
Press Contacts.
Press the menu icon.
Press Manage contacts.
Press Import/Export contacts.
Press IMPORT.
Press the name of the SIM.
Press the field above "All".
Press DONE.
Press Tablet.
Press IMPORT.
Press EXPORT.
Press the name of the SIM.
Press the field above "All".
Press DONE.
Press EXPORT.
Press OK.
Press the Home key to return to the home screen.