How to Set Up Your eSIM for Use in Japan? Explained for iPhone and Android

eSIMs are SIMs built into your smartphone, and unlike traditional physical SIM cards, they allow you to switch communication lines without physically swapping cards.
If you're currently using a physical SIM card, you can add an eSIM-compatible plan and connect to the internet using a different line than the one you're currently using.
This article explains how eSIMs work, their benefits, and how to switch from your current SIM to a different eSIM.

What is an eSIM?

An eSIM is a SIM embedded directly into your smartphone.
A SIM is an IC chip that stores subscriber identification information. Many modern smartphones support both physical SIM cards and eSIMs.
Since the IC chip that stores information for an eSIM is built into the phone, users cannot swap it out like a physical SIM card. You add or change communication lines by rewriting the eSIM information within your phone's settings.

Benefits of eSIM

Can be used as soon as the same day with an online contract

Some smartphones can use two lines (Dual SIM) No worries about loss or theft

Can be used as soon as the same day with an online contract

When you purchase an eSIM for communication in Japan online, the necessary SIM information for the eSIM can be downloaded from the internet. Unlike traditional SIM cards, there's no need to have it delivered to your home or pick it up at a store; you can activate it as soon as the same day if you contract online.
However, a Wi-Fi environment is required to download eSIM information.

Some smartphones can use two lines (Dual SIM)

Some smartphones support two SIMs, such as a combination of an eSIM and a physical SIM card, or two eSIMs.
If your current smartphone supports two SIMs, why not try adding an eSIM to use more than one line? If you can use two or more lines with one smartphone, you can consolidate your personal and business phones into a single device.
While it varies by smartphone, the limit for simultaneous use is generally two lines. However, it's common for eSIMs to support registering three or more lines. If you register lines you might use in advance on your eSIM, it's convenient to switch between them smoothly depending on the situation.

No worries about loss or theft

Since an eSIM is not a physical card, there's no concern about losing it when receiving it or changing devices, or having only the SIM pulled out if your phone is stolen.
Furthermore, even if you lose or accidentally delete an email containing the eSIM activation number, the information is often saved on the mobile carrier's member page, so you can look it up and use it. However, while an eSIM itself cannot be lost or stolen, there is still a non-zero risk of the eSIM activation number being exposed to a third party, leading to fraudulent reissuance and misuse. To prevent this risk, it's crucial to strictly manage passwords and activation numbers and utilize the security settings provided by your mobile carrier.

How to Set Up/ Switch eSIMs

This section explains how users who have a contract with their home country's carrier (via a SIM card or eSIM) can purchase an eSIM for use in Japan, complete the activation process, and switch their default data line.

Here, we will explain the basic flow of typical procedures. Actual steps may vary depending on the mobile carrier, so please be sure to refer to the guides provided by each company when actually contracting and activating your service. In some cases, proprietary apps from each company may be used to simplify the process.
This explanation assumes you are using an eSIM from Travel Mobile for use in Japan.

iPhone｜eSIM Setup and Switching Method

iPhone Setup Video

The video demonstrates how to copy and paste data without scanning a QR code, but scanning the QR code works the same way.

iPhone｜eSIM Setup and Switching Method

iPhone Setup Video

The video demonstrates how to copy and paste data without scanning a QR code, but scanning the QR code works the same way.

Android｜eSIM Setup and Switching Method

AndroidSetup Video