A SIM card or Subscriber Identity Module card is both a phone's ID tag and its key. SIM cards store your phone number, and without the card in place, you cannot make or receive calls.
Transferring your number and billing data from one iPhone to another is as easy is popping your SIM card into the new device. (You will have to transfer your contacts, photos, apps, and other data separately.)
How to remove the SIM card from an iPhone
First remove your iPhone's case (if you have one) to expose the phone itself. Then get your SIM card ejection tool, which you can purchase online . Or better yet? Grab a paperclip.
1. Locate the SIM card tray; it will be on the right hand side of your phone (as viewed from the front) and is shaped like a long, narrow oval with a small recessed hole.
2. Gently press the tip of your ejection tool or paperclip into the hole and press into the bottom of the SIM card tray until the tray pops out a bit.
3. After the tray pops open, slide it out and remove the small SIM card laying there within.
4. Reinsert the empty tray to ensure the phone maintains its resistance to dust and water damage.
5. Follow the same steps to insert the SIM card into your new phone.
When should you remove your SIM card?
In the movies, the hero pops the SIM card out of his or her phone, ducks into a crowd, and disappears. In reality, your phone can usually be tracked even without a SIM card in place.
But it can't make calls, pull up contacts, or recall past SMS messages. So when you get a new phone, don't forget to pop your SIM card out of the old one and place it in the new device.
Removing a SIM card from an old phone is also a good idea even if you won't need it in a new device, as the card will be linked to your old phone number.
And before you have your phone repaired, spend the 30 seconds to remove your SIM card. SIM cards are not very expensive (and are even given out for free by many companies), but they do contain data that could lead to some costly problems if you lose the card or it falls into the hands of a scammer.
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