On average, we keep our smartphones for about 22 months before we trade up to a new model, researchers say. That means you've probably traded your device at least once.

Before you sold, you probably copied your photos and contacts. You cleaned the screen. But did you protect your identity?

If you didn't remove your subscriber identity module (SIM) card, you might have missed a key step.

What Is a SIM Card?

A SIM card is a tiny piece of metal and plastic that sits inside your smartphone. You may not remember buying a SIM because it typically comes inside your phone when you buy it. Your card's role can vary, depending on the type of cellular company you work with. 

There are two types of mobile networks.

  • GSM: Carriers include AT&T and T-Mobile. Your SIM card contains your call records, your text messages, and other bits of data you save on your phone. This card also enables your phone to connect with your cell service. If you don't have it, your phone won't work.

  • CDMA: Carriers include Sprint, Verizon, and US Cellular. Your phone's SIM card connects you with 4G LTE networks, but it doesn't contain all of the data you'd see in a GSM card.

The short version: All SIM cards contain some tiny bits of data, and all phones need them to work properly.

Sometimes, you can pop a SIM card out of one phone, slide it into a new phone, and all your contacts and history appear in your new device like magic. But sometimes a card from your old device is too big to fit into the new one, and some bits of plastic work only in connection with one provider. If you swap servers when you change phones, the old one won't work.

3 Reasons to Remove Your SIM Card

While it's true that your SIM card probably won't work for the new owner of your phone, that doesn't mean you should leave it in when you sell. There are very good reasons to make sure this critical piece of plastic stays with you when you say farewell to your old device.

These are three good reasons to remove that card:

  1. It makes more work for your buyer. A sales transaction is delicate, and you don't want anything to break the momentum before money changes hands. Removing the card helps your buyer fall in love with your device without technology getting in the way.

  2. It protects your privacy. Researchers say we spend an average of four hours every day on our phones. Some of our activity is incredibly private. We conduct financial transactions, talk with romantic partners, and make purchases. This is data a criminal could use to steal from us, or it could be used in a blackmail scheme. Don't trust your buyer with your privacy.

  3. It could come in handy later. SIM cards can expire if you don't use them. But some carriers will let you load up a card, so you can use it as a backup when you travel or need to make a very sensitive call.

How to Remove Your SIM Card

Removing a card is really easy. It's typically located:

  • Beneath your battery. You'll pop open the door to the compartment, remove the battery, and slide out the tiny piece of plastic.

  • In a separate drawer. You'll see a small drawer on the side of your phone, with a hole on one side. Push a paperclip into that hole, and the drawer should slide open so you can pop the SIM card out.

If you're not sure where your card is or you can't get it out of your phone, talk with your phone provider. You can walk through the steps over the phone, or you can visit the nearest outpost for in-person help. 

Once you have the SIM card in your hand, you have a decision to make. Should you keep it or destroy it?

If you choose to keep your card, put it in a safe place. Slide it into an envelope, pop it into a plastic bag, or tape it to a business card. Put it in an area that's both safe and easy to remember. A desk drawer, a jewelry box, or a similar spot could be an ideal new home for your old card.

If you choose to destroy it, grab your scissors and snip across the center of the chip. You'll break the circuit, and your data will be secure. You can throw the bits into the trash.

Other Pre-Sale Steps to Take

Removing your SIM card is just one thing to do before you sell your cell. You will also need to make sure that your device is free of any other personal data, and you'll want to prepare it for a smooth sale process.  

You'll need to:

  • Check your contract. Did you lease your phone? Do you still have a few months of payment left? If so, stop right here. You can't sell something you don't own, so you'll need to work with your carrier on a solution.

  • Sign out of everything. Check through your apps, the websites you visit, and the programs you use. Make sure your login information is deleted, and if you can, remove those apps from your phone when you're done. Don't forget to check apps preinstalled on your device. Apple's "Find My Phone" function, for example, should be turned off before you sell.

  • Remove your memory card. Does your phone have an additional card for storing photos and videos? It might be stored near your SIM card, or it might be in a different spot on your phone. Check your owner's manual. You'll need to keep that card with you.

  • Back up your data. Don't let your digital present fade into the past. Back up all the information onto the cloud, and if that isn't an option, plug your phone into your computer and copy as much as you can onto your desktop. You'll lose information in the next step, so this is important.

  • Perform a factory reset. A manual deletion won't get rid of your digital fingerprints but resetting your device will. Look into the options on your phone, and search for the "factory reset" option. Know that almost everything about your phone will be wiped clean, so don't take this step until you've saved everything you want to keep.

  • Clean your device. Is your phone screen full of fingerprints and face grease? You're not alone. Use a gentle cloth to remove the goo from the surface of your phone so it's as pristine as possible for your buyer.

This may look like a long list, but don't worry. It takes just a few minutes to sever your connection with your old phone. Your buyer will thank you, and your future self will be grateful that you preserved both your data and your security during the sale of your device.


People Are Holding Onto Their Smartphones Longer. (March 2017). Business Insider.

Are You on Your Phone Too Much? The Average Person Spends This Many Hours on It Every Day. (October 2018). Inc.