What is a SIM card & how it works
What is a SIM card & how it works
Written By: Alexandra Nuschele

Phones are crucial. We use them for communicating with friends, listening to music, and Googling strange and fascinating topics. We’d be lost without our phone cameras to capture unexpected exceptional moments. But have you ever considered that all of the remarkable things is made possible by the SIM card inside?

That teeny-tiny chip is a game-changer. Furthermore, knowing all of the tricks of the trade might assist you in getting the most out of your phone. The most frequently asked SIM-related questions and their answers are listed here.

What exactly is a SIM card, and why is it so crucial? It links you to your carrier’s network, keeps track of your contacts, etc.

 What is a SIM card? 

There are two main types of mobile phones offered to consumers: GSM (Global System for Mobile) and CDMA (Code Division Multiple Access) (Code Division Multiple Access). SIM cards are used in GSM phones but not in CDMA phones.

SIM cards are small cards with a chip that must be inserted into a GSM phone for them to work. A GSM phone cannot connect to any mobile network without a SIM card. The card contains all of the necessary information.

What does a SIM do? 

eSIMs are computer chips that store data and connect you to your network. You can make calls, send SMS messages, and connect to 3G, 4G, and 5G mobile internet services. They’re also portable, and you may use them to store notes, contacts, and emails. So, if you have an accident with your phone and need to borrow someone else’s phone right away, it isn’t a problem. Simply insert the SIM card, and you may make a call or use your data. Just make sure they’re both using the same SIM card size.

 What is a Locked SIM card? 

When your phone is locked to a specific network, the phone is the one that is closed. The SIM card isn’t the issue. GSM providers can install software on phones that restrict a phone’s acceptance of a specific SIM card from a particular network. The phone will not work if the SIM card and phone do not match. When a phone is “locked,” this is what it implies.

On the other hand, unlocking a phone eliminates this restriction, allowing it to take SIM cards from various networks (find out how to remove your SIM card). If you ever want to sell your phone, keep this in mind because the buyer will need to unlock it before using it. If you’ve purchased a locked phone, the same rules apply.

How to activate a SIM card? 

As long as your SIM card is legitimate, unlocked, and provided by your network, activating it is simple. If an extra step is required, make sure you read the instructions with your new SIM attentively.

1. Make sure your phone is powered on before inserting the new SIM.

2. Use the activation key that came with your new SIM card to activate it (this will be included in the package). Valid identification may be required.

3. To activate the SIM card online, enter the code. This will necessitate internet usage (use a computer or your WiFi). Wait a few moments, and it should be active.

What information is kept on a SIM card? 

IMSI stands for International Mobile Subscriber Identity and is found on SIM cards. This number is used by the network to identify the phone. Your SIM will have a unique MSISDN in addition to your IMSI. Mobile Subscriber Integrated Services Digital Network Number is the abbreviation for Mobile Subscriber Integrated Services Digital Network Number. It’s basically your phone number, despite the fancy name.

Contact information, phone numbers, SMS messages, billing information, and data consumption can all be stored. In addition, your SIM will be protected against theft by a personal identification number (PIN).

Different types of SIM cards 

SIM cards come in three varieties. In order of size, there are three types of SIM cards: standard, micro, and nano. The Nano SIM is used by newer phones, whilst the Standard and Micro SIM are used by older phones.

Regardless, you’ll most likely be handed a Standard SIM when you buy a new SIM card, which can be converted to a smaller size for phones that support Micro or Nano-SIM.

Some phones feature eSIM, which eliminates a physical SIM card and relies on onboard SIM technology. However, to receive this, your provider must also support eSIM.

 Finding the perfect SIM card plan

The most cost-effective phone plan is anything you believe will benefit you. Changing your SIM is an excellent way to see if you’re on the right strategy. It could be time to look into whether or not other suppliers offer the benefits you desire.

A prepaid phone plan allows you to pay for a service in advance. If you’re watching your expenditures, this might be a better option.

If you like to save money and pay after you’ve tried out a service, a contractual plan is better for you. IOn the other hand, if you just want to set it and worry about it later, this option might be best for you.

The arrival of eSIM 

The industry is expected to shift to the full use of eSIMs. The SIM card is incorporated into the phone and activated remotely by the carrier, eliminating the need to fumble with microcards. Some dual-SIM devices, such as the iPhone XS, already use it for the second SIM. You’ll still need a card for your primary SIM.

However, it will take some time for this to become the norm. In the meantime, should you want to introduce yourself to eSIMs, have a look at our packages that might help you and learn more about eSIMs, check out our explanation of how they function.

Frequently Asked Questions

 Is There An eSIM On My Phone?

If your phone shows two IMEI numbers, eSIM capability means you have multiple SIM slots. The eSIM information is typically under ‘Settings’ and then ‘Mobile Network’ or ‘Mobile Data’, depending on your phone. For example, in Google Pixel 5, you need to go to Settings, Network and Internet, then the + sign next to Mobile network, which will take you to the screen where you can download an eSIM.

Which devices are compatible with eSIM?

Please go to our compatibility list to determine if your device is eSIM compatible.

Why should I buy a phone with an eSIM?

eSIM prepaid data plans are flexible and offer affordable data for any trip. eSim2go is for international travellers.


Is ESIM a Better Option Than a Physical SIM Card?

With eSIM, mobile device manufacturers can build or embed a circuit board directly inside the mobile device. Then, customers can programme the embedded SIM to register with any mobile operator. However, there may be some limitations; for example, if your eSIM enabled phone stops working, you can’t just pull the SIM out and insert it into any other phone straightaway.


Can I get a new phone that accepts an eSIM?

When it comes to mobile phones’ latest generation, most hype is about camera capabilities, screen resolution, or battery life. eSIM-enabled phones from Apple, Samsung, Google, and Microsoft are available. eSIMs were first introduced in a limited number of consumer devices in 2017.

How Does An ESIM Work?

A mobile phone with an eSIM includes a built-in microchip that may be programmed to any mobile network provider as long as the phone is unlocked. Most (if not all) eSIM-capable smartphones do not utilize eSIM as the primary SIM but rather as a secondary SIM that can operate with a traditional plastic SIM. Scanning a QR code or manually inputting the digital SIM information under phone settings may be used to download eSIM onto a phone. Unlike standard SIM cards, which must be physically inserted into a mobile device, it is a SIM that can be downloaded onto a mobile phone.

 What does eSIM mean?

The technology that allows you to utilize a digital SIM instead of a physical SIM is called eSIM. The gadget has a microchip that permits SIM connectivity, which may be configured by the user to any mobile provider as long as the phone is unlocked. Both conventional SIMs and eSIMs use the same method to connect to the mobile network. The main distinction is that physical SIMs have their own circuitry, but eSIMs program the phone’s own circuitry.

 What Are ESIM’s Advantages?

eSIM allows customers to switch from one mobile operator to another. The benefits of eSIM go beyond the phone as it can help all mobile-connected devices. However, that benefit may only apply to devices using eSIM as a replacement for the physical SIM. It is important to note that the specification for eSIM has been done by GSMA (GSM Association).

How do I set up my eSIM?

Navigate to your cell phone’s settings menu to begin the setup procedure. The settings change between Android and iPhone, and certain Android phones may also have minor differences. As a general rule, go for the section in the Settings menu where they ask for your cellular network or operator information.

After completing the setup, you may use your eSIM just like a regular SIM. You may save many profiles for various operators on your phone and switch between them. You may only use one at a time, however.

How do I get an eSIM?

If you seek an eSIM today, your cell provider will send you an ‘eSIM pack’, at least in the UK. Like a barcode, a QR code is printed on the eSIM pack. When you begin the setup procedure, you may scan the QR code, which generates an eSIM profile for the number and operator that provided the code on your phone. You can use your QR code several times if you require it, such as if you erase your profile by accident.

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