What is an eSIM? Everything You Need to Know About Virtual SIM Cards

We explain what an eSIM is, but also how to find out if your phone is compatible with this technology, what advantages and disadvantages they offer, how they work or how they are activated

What is an eSIM Everything You Need to Know About Virtual SIM Cards
Graphical representation of an eSIM, since they do not really exist physically as such

You may have heard of eSIM cards. They are becoming fashionable because they offer many advantages over traditional SIMs, especially to have mobile data when traveling to any corner of the planet. In this article we will explain in detail what an eSIM is, but also its positive and negative pointshow they work, how to know if a mobile is compatible with them and all their crucial aspects.

Table of Contents

What is an eSIM?

An eSIM (Embedded SIM = Embedded SIM) is a virtual SIM card. SIM cards (Subscriber Identity Module = Subscriber Identity Module) are those that we insert into our mobile phone to access data and calls from an operator, being basically the key to a tariff. SIMs are made up of a piece of plastic and a chip, the former holds the latter, what is really important and what the mobile phone reads.

SIM cards pictured are physical but eSIMs are not
SIM cards (pictured) are physical, but eSIMs are not

SIM cards have shrunk in size over time. They were invented in 1991 and every few years they got smaller. In fact, we call a SIM any physical card that fulfills the function of providing us with data or calls, but that would only be the name of the first one, the one from 1991.

All SIM cards:

  • SIM (1991): measured 86 x 54 mm
  • miniSIM (1996): measured 25 x 15 mm
  • microSIM (2003): measured 15 x 12 mm
  • nanoSIM (2012): 6 x 5 mm
  • eSIM (2016): Doesn’t occupy a physical location

Although there are different types of SIMs, depending on their size, and currently the most commonly used are nanoSIMs, we continue to call them SIMs.

In short, an eSIM is a SIM embedded in a device using a pre-installed chip. They serve the same function: to provide access to a mobile tariff, whether it’s data, calls, or both. They are not designed to be removed, but are kept on the mobile. They are also called virtual SIMs.

Most phones that are compatible with eSIM technology are also compatible with SIM. In this way, they can use virtual cards as well as physical ones. There are also certain exceptions, as the latest U.S. iPhones are still available. In the U.S., you no longer have a SIM slot.

eSIMs are not exclusive to mobile phones

Most users have learned about eSIMs through mobile phones, but they are not exclusive to them. They are also used in different types of portable devices with Internet access, such as smartwatches or tablets. In fact, the first to be compatible with eSIM was the Samsung Gear S2, a 2016 smartwatch that used 3G.

How to use an eSIM

Not all mobile phones can use eSIM, only those with the necessary technology. Most of the recent ones have an internal chip that makes them compatible with the technology, although this is only part of it, since you also need to have an operator that uses this technology. Therefore, the first thing is to know if your phone is compatible with eSIM.

If your mobile phone is compatible with this technology, you can contact the operator to use eSIM technology in a tariff. It will send us a letter, or e-mail, with a QR code that we must scan with the device’s camera, which will activate the initiation process. Then we just have to follow the instructions.

In the event that our device is unable to read the QR code, we can activate the eSIM from its settings. On those compatible devices, the normal thing to do is to access the settings in the Mobile networks or Tariffs section, where you will find the option. The names of the menus vary in each model, but in most it is something similar.

The Best: Ease of Travel

Using an eSIM is more convenient than a SIM. The former are neither broken nor misplacedYou also don’t need to take it out of your old phone and insert it into your new one when you change your device, which makes the process of changing easier, even if you’re not used to doing it. In addition, they allow you to use different tariffs on the same mobile phone more easily. Not to mention that it is a more advanced technology, and, partly because of that, safer.

Although we must especially take into account the travel facilities they offer. If we move around the European Union, we will have free data and calls thanks to the end of roaming in 2017, but not in territories outside the organization.

However, certain companies allow you to buy eSIMs with an unlimited amount of data or data for certain days. Their eSIMs are like those of a traditional operator, but for a territory; for example, we could buy an eSIM to have 20 GB for 30 days in the United States.

This would also be possible via SIM, but in this case we would have to order it in advance so that the physical card arrives. With eSIMs, all you have to do is buy them and redeem a QR code, as they are activated that way. The only thing it requires is an Internet connection, which can be obtained via WiFi at an airport or place with its own network. You can also activate it before your trip, so that when you arrive at your international destination, you already enjoy a connection.

Advantages and disadvantages of eSIMs

First we will show you the positive points of this type of card and then the negatives. This will help you decide whether to use them or not, but we already told you that they outperform SIMs in most aspects.

Advantages of eSIMs

eSIMs offer these advantages over SIMs:

  • They take up less space
  • Won’t break from use
  • Less likely to get lost
  • Allows multiple profiles on the same mobile
  • Increased safety as it cannot be removed
  • Allows you to change carriers without changing physical SIM
  • They are more environmentally sustainable
  • Can be activated anywhere
  • They offer advantages when traveling

In any case, the advantages escape the material plane. When used, they allow you to have several accounts or tariffs on the same device and switch between them quickly. This is something that is also possible with SIMs, since certain mobiles or devices have several SIM slots, but eSIMs make it easier as they do not take up that space.

Nor can we ignore the fact that its activation is more accessible. With SIMs we need the physical card, but with eSIMs, we don’t. Later we will delve into how they work, but you simply need a QR code and an internet connection.

Disadvantages of eSIMs

The advantages far outweigh the disadvantages. However, we must take into account the following disadvantages:

  • They can only be activated once
  • Less comfortable when switching phones
  • Not available on all devices

Currently, not all devices have eSIM technology. There are several in which it has not yet been integrated, especially those that do not belong to the high-end. As virtual SIMs are the future, this will change over the next few years, landing on everyone.

It is striking that certain mobiles only use eSIM, having replaced the traditional SIM. As previously indicated, this happens with the latest iPhone models, which in the United States no longer integrate a physical card slot and operate exclusively via eSIM.

This has indirectly led to improved operability in this aspect, with new features, such as Quick Transfer, which allows you to convert SIMs into eSIMs or transfer the eSIM from one iPhone to another iPhone.

How do I know if my phone is compatible with eSIM?

Knowing if your phone is compatible with eSIM is something we recommend you find out. Not only will it help you to use your tariff without a physical card, but also to have mobile data when you travel to a place without roaming.

All iPhones after iPhone XS, XS Max, or XR are. In other words, if, for example, you own an iPhone 11, this one will be it.

As for Android, the easiest way to do it is to look for the device’s EID number. The Embedded Identification Document is a 32-digit serial number that each mobile phone compatible with eSIM technology has. To find it, go to the calling app and dial (asterisk)#06#. Several codes will be displayed, such as the IMEI or ICCID, but the EID has to appear specifically, if it is not shown, your mobile lacks it, and, therefore, eSIM.

The quickest way is to dial *#06# in the Phone app

You can also check the specifications of your device or its box, but it’s less fast. The easiest thing to do is to do what is indicated in the previous paragraph.

The next step: iSIMs

If eSIMs are the evolution of SIMs, iSIMs are the evolution of eSIMs born in 2021. The difference between eSIM and iSIM is that the latter integrates a chip into the processor or SoC. This makes it much smaller, allowing you to use that space to enhance other parts of the phone or reduce its size.

Specifically, iSIMs are 98% smaller than eSIMs50% cheaper, and consume up to 70% less power. For this reason, its advantages extend to creation, implementation and use.

However, such technology has not yet been massively launched. Currently some SoCs support them, even the Qualcomm Snapdragon 8 Gen 1 does, but it hasn’t made it to market. It will, but not immediately.

Other frequently asked questions

We will end this article by answering other frequently asked questions about the service.

What to do if your phone with eSIM is stolen

Same as if you have a SIM. Contact your carrier’s customer service to block the card. When you have your new mobile phone, in order to use your tariff, request an eSIM change. Don’t worry, you’ll keep your same number and rate.

How to convert your old mobile number to eSIM

It depends on whether your old phone has a SIM or eSIM:

  • It has SIM: go to a store of your company and request the change from SIM to eSIM. Of course, you don’t need to have bought the smartphone with that company, it can be free or belong to another.
  • It has eSIM: you can go to a store of your company, but if you keep the QR of the eSIM, you can change it yourself by deleting the eSIM profile on the old phone and re-downloading it on the new phone.

To delete the profile on the old mobile. On Android, tap on Connections/Mobile Networks; SIM/SIM card manager; select the eSIM and tap on the delete option. Once confirmed, the eSIM profile of the old phone will be released and you will be able to scan and activate it on the new phone. On iOS it’s similar, from Settings and then to Mobile Data.

Can I have both SIM and eSIM at the same time?

Yes, the MultiSIM service allows you to use a SIM and an eSIM at the same time on different phones. This way, you can use the same number at the same rate on two different devices. It is also possible to combine a SIM and an eSIM in the same device.

Which carriers allow eSIMs

The service is gradually being implemented in more and more Spanish operators. There will come a point where they all allow it.

If your operator is one of them, you can now request your eSIM by contacting them. However, you don’t need to have an eSIM-compatible operator to use the virtual cards, they are also available on company websites whenever you want to travel and have internet on your mobile.



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