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eSIM Technology

With the eSIM, the SIM card is integrated directly into your device. In addition to many advantages, this also brings new technological possibilities for hardware manufacturers and mobile phone providers. We have summarized the most important points for you so that you can better understand what exactly is behind the term "eSIM" and how the technology works. 

Hand holding smartphone with activated eSIM tariff

How Do SIM Cards Actually Work?

Since the eSIM performs the same function as a physical SIM card, let's talk about the classic SIM card first.  

The SIM card is an integrated circuit on a plastic so-called universal integrated circuit card (UICC). That explains the "card" part, but what about "SIM"? 

"SIM" stands for "Subscriber Identity Module" or Subscriber Identification Module. The module is the metal part of the SIM card on which the circuitry is located. The purpose of the SIM is to securely store the so-called IMSI number. IMSI stands for «International Mobile Subscriber Identity» or «International Mobile Subscriber Identity». The number follows a global standard and allows a specific SIM card to be assigned to a specific customer account with your provider.

The services that you use via your mobile phone tariff will then be billed to you via this account. 

And the eSIM?

The eSIM has the same purpose, but works via a module built into the device. Hence the «e» in «eSIM»; e stands for "embedded" or "embedded". The eSIM is therefore not on a UICC, but on an eUICC, a permanently embedded circuit in the end device. 

All eSIMs are provided with a clear and unique ID, the so-called EID, directly during production. This allows mobile network providers to assign an ordered eSIM profile to the eUICC of the end device. This ensures that each profile is only used once, even without a physical SIM card. 

Incidentally, the built-in chip (eUICC) is getting smaller and smaller, just like the physical SIM card. The next step after the eSIM will probably be an integrated UICC with a so-called "iSIM".  


The SoC (System on a Chip) architecture of new computers and smartphones also allows the permanent integration of a UICC into the SoC. Until then, however, it will probably be a few more years and the eSIMs will be even smaller than they are now.

What advantages does the eSIM offer?

Space-saving design

Since the eSIM is built directly into the device, there is no need for a SIM card slot. This allows for slimmer and lighter devices that are less prone to mechanical damage.


Easy to switch cellphone providers

eSIM technology makes it possible to switch mobile operators seamlessly and without exchanging physical SIM cards. This makes it easier to switch providers and plans to find the best service for your needs.


Support for multiple cellular plans

With an eSIM, you can store multiple cell phone plans on a single device. This is particularly useful for travelers traveling in different countries who want to use local tariffs to avoid roaming charges.

How do I use an eSIM?

Activating an eSIM is very easy. After purchasing a mobile plan from an eSIM-enabled provider, you will receive an activation code that you can enter or scan on your device. Your device will then be automatically connected to the mobile network and you can get started right away.


eSIM technology is an important step towards seamless and flexible mobile communication. With the eSIM, you can easily switch between carriers and plans to get the most out of your communications and be connected exactly the way you want.

Who Is Developing the eSIM?

The GSMA or “Global System for Mobile Communications” is responsible for the development and further development of the eSIM. The GSMA is an international association of over 750 mobile phone providers who develop common standards for wireless communication via mobile phones. 


The GSMA is also responsible for the Mobile World Congress in Barcelona, the largest annual mobile industry conference in the world. 

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