What is eSIM? Basic Knowledge You Should Know Before Traveling Abroad

Recently, "eSIM" has been frequently used as a communication method for overseas travel and business trips.

eSIM is a system that allows you to add a communication plan to a compatible smartphone without replacing a physical SIM card. You can purchase it online and set it up using a QR code, allowing you to prepare your communication environment before your trip.

However, many first-time users may have questions such as:

• What is the mechanism of eSIM?
• How is it different from a regular SIM card?
• How do you set it up for overseas travel?
• Can you use phone numbers and SMS?
• Can it be used on any smartphone?

This article will clearly explain the basic mechanism of eSIM, the differences from physical SIM cards, the benefits of using it while traveling abroad, setup methods, precautions, and how to choose a plan, all in an easy-to-understand manner for beginners.

If you are looking for a communication plan to use during your trip to Japan, please check the Japan eSIM products and pricing plans.

What is eSIM?

eSIM stands for "Embedded SIM," and in Japanese, it is referred to as "組み込み型SIM" or "埋め込み型SIM."

Traditional SIM cards are used by inserting a small card into a smartphone. In contrast, eSIM has the SIM functionality built into the smartphone itself, allowing you to add communication plan information in digital form.

Since there is no need to receive or remove a physical SIM card, it is characterized by the ability to complete the purchase and setup online.

Typically, travel eSIMs are added by scanning a QR code received via email after purchase from the smartphone's settings screen.

For setup methods, please refer to the eSIM Setup Guide.

Differences Between eSIM and Physical SIM Cards

There are differences in setup methods and receipt methods between eSIM and traditional physical SIM cards.

A major feature of eSIM is the ability to add communication plans without swapping physical SIM cards.

When traveling abroad, you can reduce the risk of losing your SIM card since there is no need to remove the SIM card you use in Japan.

However, not all smartphones support eSIM. Before use, please check the list of eSIM-compatible devices.

Comparison of eSIM, SIM Cards, Wi-Fi, and International Roaming

There are several ways to access the internet while traveling abroad, including eSIM, physical SIM cards, rental Wi-Fi, and international roaming.

eSIM allows you to communicate using only your smartphone, without the need for receiving or returning a device. Therefore, it is a convenient communication method for solo travelers, short trips, and business trips abroad.

Reasons Why eSIM is Popular for Overseas Travel

Can be purchased online before departure

Travel eSIMs can be purchased online before departure, reducing the hassle of searching for SIM cards at local airports or telecom company stores.

If you choose a plan that allows you to receive a QR code after purchase, you can proceed with the setup without waiting for delivery.

No need to purchase a SIM card at the airport

There is no need to line up at the SIM card sales counter at the airport after arriving abroad.

If you install the eSIM before departure, you can turn on the line after arriving at your destination and start communication by setting up mobile data or data roaming.

Convenient when traveling to multiple countries

With a multi-country travel eSIM or global eSIM, you may be able to use it without swapping SIM cards each time you move to a different country.

It is a convenient communication method for trips such as:

• European tour
• Southeast Asia tour
• Central Asia tour
• Business trips to multiple countries
• Round-the-world trip

However, even for plans covering the same region, the supported countries may vary by product. Please check before purchase to ensure all your destinations are included in the supported countries.

You can check plans for multiple countries from global eSIM.

Can be used without increasing your luggage

There is no need to carry a dedicated router or charger like with rental Wi-Fi.

Since you can communicate using only your smartphone, it is also suitable for those who want to reduce their luggage.

Can keep your Japanese SIM card

With smartphones that support dual SIM, you may be able to add a travel eSIM while keeping your main line used in Japan.

You can set it up so that mobile data is used with the travel eSIM, while calls and SMS are handled by your main line in Japan.

However, if international roaming is enabled on your main line in Japan, there is a possibility of incurring unintended communication charges.

Benefits of eSIM

No need to swap SIM cards

Since you add the communication plan to the smartphone itself, there is no need to remove a physical SIM card.

This reduces the worry of losing your regular SIM card during your trip.

Complete the purchase and setup online

With eSIM, you can select products online and set them up using the QR code received after purchase.

There are also plans that do not require you to go to a store or wait for delivery.

Can be set up using a QR code

Many travel eSIMs can be added by scanning a QR code from the smartphone's settings screen.

This feature makes it easy for first-time users to follow the instructions after purchase and proceed with the setup.

Can save multiple communication plans

On compatible smartphones, you can save multiple eSIM profiles to the device.

You may be able to register eSIMs for different destinations, such as for Japan, South Korea, and Europe.

However, the number of eSIMs that can be saved and the number of lines that can be activated simultaneously vary by device.

Easy to choose from short-term trips to long-term stays

eSIMs come in various options, including short-term plans by the day, plans with a certain data capacity, large capacity plans, unlimited types, and multi-country travel plans.

You can choose based on the number of travel days and the intended use of data.

Disadvantages and Precautions of eSIM

Not all smartphones can use it

To use eSIM, the smartphone itself must be compatible with eSIM.

Even with the same model name, eSIM may not be available depending on the country of sale, telecom company, or model number.

Before purchasing, please check the list of eSIM-compatible devices and the manufacturer's official information.

SIM lock may need to be removed

Smartphones purchased from telecom companies may have SIM locks set.

If the SIM lock is not removed, you may not be able to communicate even if you add an international travel eSIM.

QR codes may not be reusable

The QR code for eSIM may only be usable once.

Be careful not to confuse the device you are setting up, and do not delete the installed eSIM during your trip.

Internet connection is required for setup

Downloading eSIM requires an internet connection, such as Wi-Fi.

Since you may not be able to connect to Wi-Fi after arriving at your destination, it is advisable to set it up in a stable communication environment before departure.

Timing for the start of use varies by plan

The timing for the validity period of eSIM begins varies by product.

• Starts from the time it is installed
• Starts when connected to the network at the destination
• Starts from the specified start date

If you set it up too early, the validity period may start before your trip. Be sure to check the instructions after purchase.

Data-only plans do not allow for calls or SMS

Many travel eSIMs are data-only plans.

With data-only eSIMs, you cannot make or receive calls or send and receive SMS using a regular phone number.

However, you can use internet-based calling and messaging apps like LINE, WhatsApp, and Messenger.

If you need a phone number or SMS, please check the details of the eSIM with phone number.

Communication status varies by location

Communication speed and signal quality can vary depending on the local network used, time of day, buildings, underground areas, mountainous regions, and congestion.

During your overseas trip, it is advisable to save necessary maps, hotel information, and reservation confirmations on your device.

Things to Check Before Using eSIM

Before purchasing an eSIM for overseas travel, check the following items.

• Is your smartphone compatible with eSIM?
• Is the SIM lock removed?
• Is your destination included in the supported countries?
• Do the travel dates match the plan's validity period?
• Is the required data capacity included?
• When does the service start?
• Do you need to turn on data roaming?
• Is APN setup required?
• Is tethering supported?
• Do you need a phone number or SMS?

Check the supported countries

Country-specific eSIMs, regional travel eSIMs, and global eSIMs have different countries where they can be used.

If you are traveling to multiple countries, please check that all your destinations are included in the plan.

Check the travel duration

If the available days are shorter than your travel period, you may lose communication before returning home.

Be sure to check the required number of usage days, including the arrival and departure dates.

Check the required data capacity

The required data capacity varies depending on how you use your smartphone during your trip.

For detailed data capacity estimates, please check the data usage estimates.

How to Set Up eSIM

Travel eSIMs are generally set up in the following steps.

1. Check if the device is compatible with eSIM
2. Check the status of the SIM lock
3. Select a plan based on destination, usage days, and data capacity
4. Purchase eSIM online
5. Receive the QR code via email
6. Add eSIM from the smartphone's settings screen
7. Scan the QR code
8. Give the added eSIM a recognizable name
9. Turn on the eSIM line after arriving at the destination
10. Select the travel eSIM for mobile data communication
11. Turn on data roaming if necessary
12. Turn off Wi-Fi and check the connection

For detailed setup instructions, please check the eSIM Setup Guide.

If Setting Up on iPhone

1. Open "Settings"
2. Select "Cellular"
3. Select "Add eSIM"
4. Select "Use QR Code"
5. Scan the QR code received after purchase
6. Select the travel eSIM for mobile data communication
7. Turn on data roaming for the travel eSIM

If Setting Up on Android

1. Open "Settings"
2. Select "Network & Internet," "Connections," "SIM," etc.
3. Select "Add SIM" or "Add eSIM"
4. Scan the QR code
5. Select the travel eSIM for mobile data communication
6. Turn on data roaming for the travel eSIM
7. Set up APN if necessary

On Android, the menu names may vary depending on the manufacturer, model, and OS version.

Can You Use Phone Numbers and SMS with eSIM?

Whether you can use phone numbers and SMS with eSIM depends on the plan you purchase.

Typical overseas travel eSIMs come in the following types.

Even with a data-only eSIM, you can use internet-based calls with apps like LINE, WhatsApp, and Messenger.

If you want to make regular calls to hotels or restaurants or receive SMS, consider a plan with a phone number.

However, even with an eSIM that has a phone number, it may not be usable for all SMS verifications.

For more details, please check Can You Use a Phone Number with eSIM? How to Choose Plans for Calls and SMS.

Global eSIM is Recommended for Overseas Travel

Global eSIMs that support multiple countries are suitable for the following individuals:

• Those planning to travel to multiple countries
• Those who do not want to swap SIM cards for each country
• Those visiting multiple countries for business trips
• Those whose travel schedule may change
• Those planning a round-the-world trip

When choosing a global eSIM, check the supported countries, available days, data capacity, communication speed, tethering, and start conditions.

You can check overseas travel plans from global eSIM.

If you are planning to travel to Japan, please check the Japan eSIM products and pricing plans.

What to Check if eSIM is Not Connecting

If you cannot connect after arriving at your destination, check the following items before deleting the eSIM.

1. Check if the eSIM line is turned on
2. Check if the travel eSIM is selected for mobile data communication
3. Turn on data roaming for the travel eSIM
4. Turn off Wi-Fi and check the connection
5. Turn on airplane mode and then turn it off
6. Restart the smartphone
7. Check if APN setup is required
8. Set network selection to automatic
9. Check if your current location is included in the supported countries
10. Check the start date and validity period

If the settings do not improve the situation, do not delete the eSIM. Instead, prepare your order number, device name, OS, settings screen, error messages, etc., and contact support.

For detailed troubleshooting methods, please refer to What to Check When eSIM is Not Connecting.

Frequently Asked Questions About eSIM

Can eSIM be used on any smartphone?

Not all smartphones can use it.

It must be an eSIM-compatible device, and the SIM lock must be removed if necessary.

Before purchasing, please check the list of eSIM-compatible devices.

When should I set up eSIM?

It is recommended to complete the installation before departure in a stable Wi-Fi environment.

However, some products may start the validity period from the time of installation, so check the start conditions before setup.

How long does it take to set up eSIM?

It varies depending on the device and communication environment, but generally, it can be set up in a few minutes to about 10 minutes.

Can the eSIM QR code be used multiple times?

It varies by product, but some QR codes can only be used once.

Be careful not to confuse the device you are setting up, and do not delete the eSIM immediately if you cannot connect.

Can I use it right after arriving abroad?

If you complete the installation before departure and correctly set the line, mobile data, and data roaming after arriving, you can use it after connecting to the local network.

Can I use LINE or WhatsApp with eSIM?

If the plan supports data communication, you can use LINE and WhatsApp for messaging, voice calls, and video calls.

Does eSIM come with a phone number?

Typical travel eSIMs are data-only and do not come with a regular phone number.

If you need a phone number or SMS, please check the eSIM with phone number.

Can I tether with eSIM?

Whether tethering is possible depends on the plan and smartphone you are using.

If you plan to connect a computer or tablet, please check the product page before purchasing.

What happens if I accidentally delete eSIM?

You may not be able to reinstall it with the same QR code.

If you accidentally delete it, please check with support to see if a new QR code can be issued.

Conclusion | Check the Basics of eSIM Before Traveling Abroad

eSIM is a convenient system that allows you to add a communication plan to your smartphone without swapping physical SIM cards.

When traveling abroad, it offers the following benefits:

• Can be purchased and set up online before departure
• No need to swap SIM cards
• No need for pickup or return at the airport
• Can choose plans that support multiple countries
• Can communicate using only your smartphone
• Easy to start communication right after arriving

On the other hand, you need to check the following before use:

• Is your smartphone compatible with eSIM?
• Is the SIM lock removed?
• Is your destination included in the supported countries?
• Do the travel dates match the plan's validity period?
• Is the required data capacity included?
• When does the service start?
• Do you need to turn on data roaming or set up APN?
• Do you need a phone number or SMS?

Check your travel schedule, destinations, and intended data usage, and choose an eSIM plan that suits you.

You can check overseas travel plans from global eSIM. If you are planning to travel to Japan, please also check the Japan eSIM products and pricing plans.