What is an iPhone SIM Card?

iphone SIM card
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You may have heard the word "SIM" used when talking about the iPhone and other mobile phones but how much do you know about what it means? This article explains what a SIM is, how it relates to the iPhone, and what you need to know about it when using your iPhone.

SIM Explained

SIM is short for Subscriber Identity Module. SIM cards are small, removable smart cards used to store data like your mobile phone number, the phone company you use, your billing information and, in some cases, your address book data.

They're a required part of virtually every cell, mobile, and smartphone.

SIM cards can be removed from one phone and inserted into others, so they allow you to easily transport phone numbers stored in your phone's address book and other data to new phones. Just swap the card to a new phone. (It's important to note that this applies to SIM cards generally, but not to the iPhone. More on that later.)

SIM cards being swappable also makes them useful in international travel. If your phone is compatible with the cellular networks in the country you visit, you can purchase a new SIM in another country, put it into your phone, and make calls and use data like a local, which is cheaper than using an international data plan.

Not all phones have SIM cards. Other phones have them but don't allow you to remove them.

What Type of SIM Card Each iPhone Has

Every iPhone uses a SIM card. There are three types of SIMs used in iPhone models:

  • SIM: This is the original type of SIM. The full SIM is the size of a credit card, but the part that contains the important data can be popped out of the larger card and used in a phone. 
  • Micro SIM: When the iPhone 4 debuted in 2010, it was the first smartphone from any company that used the Micro SIM format. The Micro SIM is substantially smaller than the original SIM.
  • Nano SIM: The Nano SIM debuted in the iPhone 5 in 2012. The Nano SIM is about 12% smaller than the Micro SIM.

The SIM type used in each iPhone is:

iPhone ModelsSIM Type
Original iPhoneSIM
iPhone 3G and 3GSSIM
iPhone 4 and 4SMicro SIM
iPhone 5, 5C, and 5SNano SIM
iPhone 6 and 6 PlusNano SIM
iPhone SENano SIM
iPhone 6S and 6S PlusNano SIM
iPhone 7 and 7 PlusNano SIM
iPhone 8 and 8 PlusNano SIM
iPhone XNano SIM

Not every Apple product uses one of these three SIMs. Some iPad model that connect to 3G and 4G cellular data networks use an Apple-created card called an Apple SIM. You can learn more about the Apple SIM here.

The iPod touch does not have a SIM. Only devices that connect to cellular phone networks need a SIM, and since the touch doesn't have that feature, it doesn't have one.

How SIM Cards Are Used in the iPhone

Unlike some other mobile phones, the iPhone's SIM is only used to store customer data like phone number and billing information.

The SIM on the iPhone can't be used to store contacts. You also cannot back up data to or read data from the iPhone's SIM. Instead, all data that would be stored on the SIM on other phones is stored in the iPhone's main storage (or in iCloud) along with your music, apps, and other data.

So, swapping a new SIM into your iPhone won't affect your access to the address book and other data stored on your iPhone.

Where to Find the iPhone SIM on Each Model

You can find the SIM on each iPhone model in the following locations:

iPhone ModelSIM Location
Original iPhoneTop, between on/off button
and headphone jack 
iPhone 3G and 3GSTop, between on/off button
and headphone jack 
iPhone 4 and 4SRight side
iPhone 5, 5C, and 5SRight side
iPhone 6 and 6 PlusRight side, below on/off button
iPhone SERight side
iPhone 6S and 6S PlusRight side, below on/off button
iPhone 7 and 7 PlusRight side, below on/off button
iPhone 8 and 8 PlusRight side, below on/off button
iPhone XRight side, below on/off button

How to Remove the iPhone SIM

Removing your iPhone's SIM is simple. All you need is a paperclip (or the "SIM Removal Tool" that Apple includes with some iPhone models).

  1. Begin by finding the SIM on your iPhone.
  2. Unfold a paperclip so that one end of it is longer than the rest.
  3. Insert the paperclip into the tiny hole next to the SIM.
  4. Press (but not too hard!) until the SIM card pops out. 

These steps are good to know when your iPhone gives a SIM not found error. Fixing that is problem requires a very similar technique.

SIM Locks

Some phones have what is called a SIM lock. This is a feature that ties the SIM to a specific phone company (usually the one that you bought the phone from originally). This is done in part because phone companies sometimes require customers to sign multi-year contracts and use a SIM lock to enforce the contracts. 

Phones without SIM locks are referred to as unlocked phones. You can usually purchase an unlocked phone for the full retail price of the device. After your contract ends, you can unlock the phone for free through your phone company. You can also unlock phones via phone company tools and software hacks.

Does the iPhone Have a SIM Lock?

In some countries, especially the U.S., the iPhone has a SIM lock. A SIM lock is a feature that ties the phone to the carrier that sold it to ensure that it works exclusively on that carrier's network. 

It is also possible to purchase an iPhone without the SIM lock, meaning it can be used on any compatible cell phone network.

Depending on the country and carrier, you can also unlock an iPhone after a certain period of time under contract.

Can You Convert Other SIM Sizes to Work With iPhone?

Yes, you can convert many SIM cards to work with the iPhone. This allows you bring your existing service and phone number from another phone company to the iPhone. Do this you, you have to cut your existing SIM down to the size of the Micro SIM or Nano SIM used by your iPhone model. There are some tools available to ease this process (compare prices on these tools). This is only recommended for a tech-savvy and those willing to take the risk of ruining their existing SIM card and rendering it unusable.