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What really happens when you switch your SIM card

By Mint Team

Originally published March 29, 2022


Last Updated March 19, 2024

mint fox explaining what really happens when you switch your sim card

You may already know what a SIM card is and how to remove yours from your iPhone or Android device. But you’re probably wondering what exactly happens when you move your SIM card to another phone or get a new SIM card altogether. The short answer? Not much. All the really important stuff is either on your account or saved to your phone, so switching SIM cards isn’t too risky. Keep reading to learn more about what information is stored on a SIM card and what happens when you decide to switch things up. We’ll begin with moving your SIM card to another phone.

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What happens when you switch your SIM card to another phone?

A SIM card is essential to most of your phone’s basic functions, so it must be loaded with all kinds of important information, right? Well, kind of. It contains your phone number, which is connected to your account with your wireless provider, and it houses a SIM, which connects your phone to a wireless network. But everything else stays on your phone when you remove the SIM card.

Your phone number follows your SIM card

The simplest way to describe a SIM card would be to say that it contains your account information. SIM stands for Subscriber Identity Module, so a SIM card is a card with a module in it (like a memory card or microchip) that contains a subscriber’s identity (i.e. phone number). When a friend of yours dials your phone number, it travels through the network to your SIM card, which then tells your phone to ring. This means that whatever phone you put your SIM card in will then have your phone number – as long as it’s unlocked, of course.

Everything else stays on your phone

Your contacts, messages, apps, wallpaper and pretty much anything else that isn’t your phone number will stay on your phone – even if you take the SIM card out. No need to worry about losing your email settings or your entire contact list (we get it, nobody knows anyone’s phone number anymore). However, because your SIM card is critical to connecting your phone to a wireless network, any apps or games that rely on an internet connection may not work without it. And as you may have guessed, no phone number in your phone means no calling or texting. Losing these capabilities is only temporary of course. Once you reinsert your SIM card in your phone and get your signal bars back, everything will return to normal and you won’t lose any data or information. Your message threads, email settings and high scores are all safe.

If you’re moving your SIM card to your new phone, chances are you’ll need to move that other stuff too. Transferring contacts, apps, and other content is relatively easy if you follow the steps provided by the device manufacturer.

What happens when you replace your SIM card?

There will likely come a time when you need to replace your SIM card. They get lost, damaged, or you may need a new SIM because you got a new phone (or a whole new wireless provider). Luckily, replacing your SIM card is almost as easy as moving it from phone to phone.  

Getting a new SIM card for your current phone

When you’ve had the same wireless service for years, there may come a time when you need a new SIM card. If your SIM stops working, you’ll need to contact your current wireless provider and in most cases, they’ll send you a new SIM card in the mail with activation instructions. Following the instructions carefully should move your phone number from your old SIM card to the new one in a matter of minutes. Then you should be able to just take the old SIM card out of your phone and install the new one. Easy peasy. 

Getting a new SIM card because you got a new phone

Oftentimes when you upgrade your phone, it will come with a new SIM card. You may be able to just move your current SIM card from your old phone to the new one and hold onto this new SIM card for later, but sometimes your new phone will require the new SIM card. In the last few years, iPhones & Android devices have moved from the standard SIM card size to micro SIM cards, and most recently nano SIM cards. So if you’ve upgraded from a phone that takes a standard SIM card to one that takes a nano SIM card, your current SIM card is just too big. 

Your new SIM card should come with activation instructions, so just follow those carefully, insert the new SIM card into your new phone and test it out with a call or a text. Then you can start going through the process of transferring over everything else.  

explaining what happens when getting a new sim card

Getting a new SIM card because you switched to a new carrier

If you ditched your previous cell phone carrier for someone new (someone who offers premium wireless for as low as $15/month perhaps?), then you’ll definitely need a new SIM card. If you’re transferring your number from your previous carrier, you’ll want to make sure you don’t cancel that line before activating with your new carrier. Your new wireless carrier will assist you with making sure your phone number moves from your old SIM card to your new one. 

Your new carrier’s SIM card may fit in your phone, but if that phone is still locked to your previous carrier’s network, you’ll probably receive a SIM error. If you wish to keep your phone with your new wireless service, you’ll have to reach out to your previous carrier and request that your phone be unlocked. Unlocking your phone allows it to accept any carrier’s SIM card, and just like inserting a new SIM card, has no effect on your apps, photos or anything else on the phone. 

Getting a new SIM card temporarily while traveling

Whenever you travel outside your usual coverage area, you risk racking up charges thanks to “roaming.” This is when your phone, with your primary carrier’s SIM card inside, connects to another carrier’s network and “borrows” their service to make & receive calls or send & receive text messages, at a fee. To avoid roaming fees, many travelers will bring an unlocked phone with them and pick up a local SIM card from whichever carrier services the area they’re in. If you ever go this route, remember that getting a new temporary SIM card from a different carrier means getting a new plan and new phone number, too. So maybe text your mom ahead of calling so she knows that unknown number is you. Who are we kidding, your mom probably answers unknown numbers all the time.

Now that you’ve gotten this crash course in SIM card switching, it’s time to take a moment and decide if you like the SIM card you have currently. As we said earlier, switching to a different wireless carrier is as easy as switching your SIM card. Take a peek at the phone plans we have to offer and consider BYOP (that’s “bringing your own phone”) over to Mint Mobile. You’ll be glad you did. And on the off-chance you decide not to stick with Mint Mobile, you can always just switch SIM cards again. It really is that easy.

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