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What is stored on a SIM card?

By Mint Fox

Originally published April 26, 2022


Last Updated March 12, 2024

Mint Fox examining a SIM card with a magnifying glass. Graphic copy reads: “What is stored on a SIM card?”
In this article

Maybe you just found out what a SIM card is, or maybe you’re swapping cards and you’re curious what’s actually going on inside your SIM card. The answer is that SIM cards store data specific to you, the phone user, including things like your phone number. 

SIM cards also have an ID number, or international mobile subscriber identity (IMSI), attached to them, as well as a personal identification number (PIN) to protect against theft. The IMSI identifies the phone to your network and lets the network know if there’s an active subscription tied to it. 

Here is some other information stored on your SIM card:

  • Advice of Charge: This estimates the cost of mobile services for your phone.
  • Authentication Key: This is a unique value for each SIM that authenticates it for the network it’s running on. 
  • Mobile Country Code: This one is pretty aptly-named–it shows which country you’re calling from.
  • Local Area Identity: This is another identifying code combined with your phone number and mobile country code.
  • Service Dialing Number: These are numbers that can be dialed to tell you things like your current balance. 
  • Service Provider Name: This is the name of your mobile operator–like us, for example.
  • Short Message Service Center: This is what delivers your text messages.
  • Unblocking Code: If you’re all thumbs, this is the code needed to open your phone if you keep putting in the wrong PIN.
  • Integrated Circuit Card ID: This is another unique number for your SIM card that helps identify it. Like snowflakes, all of them are unique and no two SIM cards have the same number.
  • Voice-added Services: These are any additional services for your phone that you’ve purchased.

Physically, sometimes the area on your phone that contains the SIM tray will also host your IMEI number. What the f*! are we talking about (we said fox)? Click the link to find out.

How much data can a SIM card store?

SIM cards have storage capacities that usually range from 8KB to 256KB, which totals up to about 250 contacts, some messages, and some of your other key data.

What does a SIM card hold?

As we said above, if you’re wondering what information is on a SIM card, a SIM card holds data specific to the phone’s user, including your phone number, as well as safety measures like your PIN and numbers relevant to your mobile provider, like your international mobile subscriber identity. eSIM cards also hold similar data.

Does a SIM card store data?

Yep, SIM cards do store data, like your phone’s information. They can also show your data usage. They can’t show many turns it took you to finish your Wordle for the day though, so make sure to tell the group chat.

Does a SIM card hold pictures?

Photos aren’t stored on your SIM card, which makes it important to back up your photos if you ever decide to switch your SIM card out. If you have an iPhone, consider saving them to iCloud, or if you have an Android, save them to your SD card.

Is your phone number stored on SIM cards?

Yep, SIM cards have a mobile subscriber integrated services digital network number—a.k.a. your phone number. 

Are texts stored on SIM cards?

Yes, SIM cards are capable of storing a portion of your messages (the number depends on how much your SIM card can store). But in general, for modern phones, most of your messages are actually stored on the device itself or in cloud storage.

Is browser history stored on SIM cards?

Nope, SIM cards don’t hold your browser history on them. Only your internet browsers, like Safari or Firefox, hold that kind of info. So feel free to get into niche internet fights without judgment from us.

Does a SIM card hold contacts?

In the past, a SIM card could hold up to 250 contacts. However, most modern phones store your contacts in cloud storage or on the device itself.

Mint Fox on his phone checking to see what’s stored on his SIM card

How do I see what is stored on my SIM card?

There are a few different ways to see what’s on your SIM card. One option is to buy a SIM card reader, which is a separate piece of hardware that can transfer your SIM card’s data to your computer and make it visible to you.

On an iPhone, you can tap Settings > Cellular > Cellular Data Option to view your account and see info on your SIM card, including account type. You can also see if any apps are using SIM card data by going to Settings > Sim Applications. 

On an Android, you can go to Settings > About Phone to see your SIM’s status and info like your phone number, roaming info and more.

Does taking out your SIM card delete everything?

The short answer is: nope. The shorter answer is: no. Taking out your SIM card will not delete all of your data. Everything important is already saved to your phone (or iCloud, in the case of an iPhone). You’ll still have your contacts, messages, app and even your wallpapers. Find out more about what happens when you switch your SIM card via our guide. One thing that will be removed is your phone number, since that information is tied to your individual SIM card. But luckily, your number will function again as soon as you put the SIM card back in.

Can’t get enough about SIM cards?

You’re in luck. Check out our video that also covers what’s on a SIM card, but with the added bonus that the info is delivered by a fox-y guy in glasses:

If you’re good to go re: what’s on a SIM card, take a peek at our page detailing everything else you could ever want to know about SIM cards. Or you could go ahead and learn more about what Mint Mobile has to offer.

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