What is eSIM? Explaining the pros and cons, and who eSIM is recommended for

"What exactly is an eSIM?"
"I want to know the benefits of using an eSIM instead of a SIM card."
Although many people have heard of eSIMs, they may not yet fully understand how they differ from SIM cards and their unique features.
In this article, we will introduce in detail the features, advantages and disadvantages of eSIMs, and how they differ from SIM cards.
In the latter half of the article, we also touch on the eSIM activation procedure and who we recommend using eSIMs for, so please take a look.

Table of contents

What is eSIM?

eSIMとは、従来の物理的なSIMカードとは異なり、スマートフォンやタブレットに内蔵されている電子チップのことを指します。

物理的なSIMカードの代わりに、デバイスに差し込むものではなく、スマホやタブレットにあらかじめ組み込まれているため、物理的なSIMカードの挿し替えが不要です。

eSIMの大きな特徴は、携帯キャリアのプロファイルを電子的にダウンロードすることで、回線契約を行える点です。

例えば、新しいキャリアに乗り換える時には、店頭に行ってSIMカードを受け取る必要がなく、スマホからオンラインで契約を完了し、その場で使えるようになります。

eSIMが登場してからは、その利便性から徐々にeSIM対応機種が増えています。

また、総務省も2021年8月に、eSIMについて「利用者の事業者変更の円滑化や利便性向上に資するもの」として、その普及・促進に向けたガイドラインを公表しています。

Reference: *1: Reference: "Direction of Consideration (Draft)" (Ministry of Internal Affairs and Communications)

The difference between a SIM card and an eSIM

Here we will introduce the difference between SIM cards and eSIMs.

SIM Card

SIM is an abbreviation for "Subscriber Identity Module," which literally means "subscriber identification module."

To put it simply, a SIM card is a card that stores smartphone subscriber information (identification number, phone number, and email address).

By inserting a SIM card into a device such as a smartphone or tablet, you can make phone calls and use data communications.

There are also different sizes available, and if you do not choose the right size for your smartphone, you will not be able to use the smartphone itself.

Please also keep in mind that nanoSIM is the mainstream of smartphones currently on the market.

For more information about SIM cards, please refer to the following article:

Reference: What is a SIM card? Explaining its role, types, and precautions when using it

Reference: You can change your SIM card yourself! Explaining the preparations and precautions to take when changing your SIM card

eSIM

The SIM card was the card that recorded the subscriber's information.

On the other hand, eSIM is a type of SIM in which subscriber information is recorded on a chip embedded in the device rather than on a card.

We will introduce the specific benefits later, but because it is built into the device, you can make voice calls and use data communications by downloading a profile (subscriber information) using a dedicated app or QR code.

Unlike SIM cards, there is no need to swap cards between devices when switching carriers.

Five benefits of eSIM

From here, we will introduce the benefits of eSIM from five perspectives, such as the convenience of being able to complete the procedure online and the hassle of not having to replace it.

The process is quick as it can be activated online

Even when activating a SIM card with a carrier, online procedures have become common, but there is still a waiting period while the SIM card is mailed to you.

On the other hand, eSIM does not require a card, so you can activate it using just one smartphone via the carrier's application page as long as you are in a Wi-Fi network environment.

There's no need to go to the store, and you can get your card activated as soon as the same day.

There is no need to replace the physical card

An eSIM is a SIM built into the device, so no physical card is required.

If you are switching carriers using a SIM card, you will need to insert the new card sent to you by your contracted carrier into your smartphone.

On the other hand, with eSIM, the process can be completed online, eliminating the need to go through the hassle of replacing cards.

Low risk of loss or damage

When switching smartphone carriers, you will need to replace the physical card with a new SIM card.

If moisture, dust, or dirt gets on the surface of the card when you replace it, there is a risk of it breaking.

On the other hand, eSIMs are built-in, so unless you take the trouble to disassemble them, they will not be exposed to moisture, dust, or dirt.

As such, the advantage of using eSIM is that there is less risk of loss or malfunction.

Easy to use overseas

If you want to use a SIM card overseas, you will need to purchase the card in advance or purchase one locally and insert it into your smartphone.

With eSIM, you can complete the process online even with an overseas carrier, so there is no need to replace the SIM card, making it easy to use overseas.

If you are considering using a SIM card overseas, we recommend the following article, which summarizes how to purchase, choose, and use a SIM card.

In addition to SIM cards, we also explain povo2.0 (*2) international roaming (*3), which allows you to use the mobile network of your destination carrier from the carrier you currently have a contract with in Japan.

Reference: What is an overseas SIM card? A detailed explanation from how to purchase to how to use it

*2: As this is an online-only plan, all procedures and support will be handled online. Please contact us via the povo2.0 app or official website. *3: Not available with "povo2.0 Data Only."

Dual SIM allows you to use multiple lines

Dual SIM is a system that allows you to set two SIM cards in one smartphone and use two phone numbers and communication lines.

Some dual SIM-compatible smartphones can use both eSIM and SIM cards, and with these smartphones you can use them for each line as follows:

Of course, some dual SIM models allow you to insert two SIM cards.

However, if you have a model that can combine an eSIM and a SIM card, it is less of a hassle to swap SIM cards than models that require two SIM cards.

Reference: The benefits of using multiple lines on one smartphone are here

Four disadvantages of eSIM that you should be aware of beforehand

eSIM has advantages such as "no need to replace physical cards" and "less likely to be lost or broken."

Although eSIM has many advantages, it also has some disadvantages that you should be aware of in advance.

Here are four disadvantages:

There are also smartphones and carrier plans that do not support eSIM

Major carriers started using eSIM in 2021, but not all carriers and models support eSIM.

You should check the official website of the carrier you are considering to see how well it supports eSIM.

You may need a separate device to display the QR code.

When signing up for an eSIM, device and user information is not initially written into the contract.

Therefore, you will need to download the eSIM profile (subscriber information) yourself and perform the initial settings.

In this case, you may not be able to download the profile and may have to use a different device to set it up using a QR code.

In that case, you will need to prepare a separate device, so be careful.

Wi-Fi environment required

The eSIM activation procedure is set up online, so one disadvantage is that it cannot be completed unless the network environment is in place.

If you have Wi-Fi at home, there's no problem, but if not, you'll need to make preparations such as setting up or finding a Wi-Fi environment.

You need to do the procedure yourself

As explained above, the activation process for an eSIM can be completed entirely online, which means that, for better or worse, you will essentially have to complete the activation process yourself.

This may be fine for those who don't mind it, but for those who are unfamiliar with using smartphones or the Internet in general, the process may be a hurdle.

Who is eSIM suitable for?

So far we have looked at the advantages and disadvantages of using eSIMs, but from here on we will take a closer look at the types of people for whom eSIMs are recommended from the perspective of convenience.

I want to quickly complete the activation procedures and switch carriers.

The activation process for eSIM can be completed online, so it is especially recommended for those who want to apply and start using it immediately.

For example, in the case of povo2.0, if you are in a Wi-Fi environment after applying, activation can be achieved on the same day (*4).

We can accommodate a variety of needs, such as "I absolutely need to have it activated by tomorrow for fees reasons" or "I need to switch to a different plan at the end of the month, so I need it activated smoothly."

*4: If you complete the procedure after 8:00 PM, the service will be activated after 9:30 AM the following day.

I want to use multiple SIM cards at the same time

If you want to use multiple SIM cards simultaneously, for example, to have separate carriers for personal and work use, or to have a stable internet connection in case of communication outages, we recommend a dual SIM-compatible model with an eSIM.

Additionally, if you are considering owning two smartphones, you can reduce the burden of owning two devices by using a dual-SIM compatible eSIM, which means you only need one smartphone.

If you use multiple SIM cards at the same time, you can increase your chances of getting the best deal from your carrier by considering the following combinations:

No resistance to online procedures

If you regularly sign up for online services, such as shopping on e-commerce sites or subscribing to services, you will likely have little trouble with the eSIM process.

On the other hand, those who are uneasy about not receiving face-to-face support may find eSIM, which can be completed online, to be a hurdle.

If you have any concerns, it may be a good idea to choose a carrier that will assist you with the activation process in-store, although there may be an additional fee.

I want to use the internet smoothly even when I'm overseas

With eSIM, there is no need to replace the SIM card, and the procedure can be completed online, so even if you need a SIM card locally, you can activate it smoothly.

Another factor that allows for smooth activation is that there is no risk of SIM cards running out of stock or the hassle of procuring them, which are common with SIM cards.

Preparations for eSIM activation

So far, we have introduced the advantages and disadvantages of eSIM, as well as the characteristics of people for whom eSIM is recommended.

Here we will look at the preparations you need to make before opening.

Prepare a Wi-Fi environment

The initial setup requires communication via Wi-Fi, so proceed with the setup in a location where Wi-Fi is available.

Prepare a device other than a smartphone to set up the eSIM, such as a computer or tablet.

When activating an eSIM on your smartphone, you can activate the SIM by displaying a QR code® (activation code) on another device such as a computer or tablet.

In this case, you will need to prepare a device that can display QR codes.

However, depending on the carrier, you may be able to proceed with the activation procedure with just one smartphone, so please check with the carrier you plan to switch to for details.

povo2.0 also offers a "code entry method" that allows you to set up the eSIM on one device without needing a separate device if you are unable to download a profile during the eSIM activation procedure.

Please check the link below for the procedure for activating povo2.0 eSIM.

Reference: "eSIM activation procedure" (povo2.0)

Check if your device supports eSIM

Before activating an eSIM, you need to check whether you have a model that supports eSIMs. (The same applies when purchasing a new model.)

You can check which devices have been confirmed to work with eSIM in povo2.0 via the following link.

Reference: "Compatible Devices (Devices Tested for Operation)" (povo2.0)

eSIM非対応端末をご利用の場合や、デュアルSIM対応端末への買い替えをご検討中の場合は、povoで取り扱っている認定中古スマホもご検討ください。

参考： 「povo 認定中古スマホ」（povo2.0）