Switching between SIM cards

There should be no problem in switching SIMs like that.

 

To be safe although not needed jus turn off facetime and imessage before switching out SIM 1 and then turn em both back on after inserting SIM 2....also I hope your iPhone is unlocked...only then will you be able to insert another carrier sim card...

 

If I am constantly switching between two SIM cards on one unlocked iphone (3GS), what happens to my message history? Is there a separate message history for the first SIM card, and then when I change to the second SIM card I only see the message history for that card?

Is it the same with Whatsapp?

I assume the contacts are centrally stored on the iphone and they are the same regardless of what sim card.

If you sync to iTunes, then does it sync message and call history for both SIM cards?

Thanks!!

 

I agree here. It seems to keep the activation time down when swapping Sims. Should have no other problems, with the acception of sometimes being prompted to enter the voice mail password.

 

Correct, voicemail password will be the only thing that will be necessary to do after switching the card.

As for your contacts, these are stored locally on the iPhone and not the SIM card. Same goes for all Messages.

Think about it this way: All the SIM card does for an iPhone is tell it which carrier you have and your phone number. Everything else is done by the phone itself.