How to use tethering while traveling in Japan: Required data capacity and points to note.

If you want to connect your computer or tablet to the internet while traveling in Japan, the tethering feature of your smartphone is very convenient.

By using tethering, you can use your smartphone as a Wi-Fi router and share the data connection of your Japan eSIM with other devices.

However, many people may wonder, "Can I use tethering with a travel eSIM?" "What GB do I need for work?" "Can I use unlimited plans on my computer without restrictions?"

The availability and conditions for tethering vary depending on the eSIM product. Additionally, since computers automatically perform app updates and cloud synchronization, they may consume more data than using just a smartphone.

In this article, we will explain in detail how to use tethering on iPhone and Android during your trip to Japan, the necessary data capacity, ways to save on data usage, and points to note when using it.

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What is Tethering?

Tethering is a feature that allows you to use your smartphone's mobile data connection to connect devices such as computers, tablets, and gaming consoles to the internet.

Since the smartphone acts as a mobile Wi-Fi router, you can communicate with multiple devices without needing to carry a separate rental Wi-Fi device.

There are mainly three methods of tethering:

If you want to use it easily while traveling, Wi-Fi tethering is the most common choice.

If you need to stay connected for long periods for work, consider USB tethering for stability and charging.

Can I Use Tethering with a Japan eSIM?

If you have a Japan eSIM that supports tethering, you can share your smartphone's data connection with a computer or tablet.

However, not all eSIM products support tethering.

Before purchasing, please check the following items on the product page or usage conditions:

• Is tethering supported?
• Is there a limit on tethering capacity?
• Are there speed restrictions even on unlimited plans?
• What is the daily high-speed data capacity?
• What is the communication speed after exceeding the capacity?
• Can multiple devices be connected simultaneously?

When comparing the prices and usage days of Japan eSIM, please check Japan eSIM Pricing and Plan Comparison.

Points to Consider When Choosing a Tethering-Compatible eSIM

Check for Tethering Compatibility

Check if the product page mentions "Tethering available" or "Internet sharing supported."

If there is no mention, it is advisable to contact the seller before purchasing for peace of mind.

Check the Data Capacity Limit

Using tethering on a computer consumes more data compared to using maps or messages on a smartphone alone.

With low-capacity plans, you may run out of data even with short work sessions, so choose a plan that fits your usage purpose.

Check the Conditions for Unlimited Plans

Even if it says "Unlimited data," some products may impose speed restrictions after exceeding a certain amount.

Additionally, while the smartphone's data communication may be unlimited, there may be a separate limit set for tethering.

Check the Usage Period

If you choose a plan shorter than your travel days, there is a possibility that the usage period will end during your stay.

Please check the start date, end date, and validity period in local time.

Check the Communication Area

While there are many places in urban areas of Japan where communication is easy, signal strength may weaken in mountainous areas, remote islands, underground, tunnels, and deep inside buildings.

The quality of tethering communication is affected by the signal conditions received by the smartphone.

How to Use Tethering on iPhone

On iPhone, you can set up tethering from "Internet Sharing."

1. Turn ON the Japan eSIM line
2. Open "Settings"
3. Select "Mobile Data"
4. Select the Japan eSIM for mobile data
5. If necessary, turn ON data roaming for the Japan eSIM
6. Select "Internet Sharing"
7. Turn ON "Allow Others to Join"
8. Check the displayed Wi-Fi password
9. Select the iPhone's network name from your computer or tablet
10. Enter the password to connect

The names of the settings may vary depending on the iOS version and contract details.

If "Internet Sharing" is not displayed, please check the line settings, APN, and tethering compatibility of the Japan eSIM.

How to Use Tethering on Android

On Android, it is displayed under names like "Access Point" or "Mobile Hotspot."

1. Turn ON the Japan eSIM line
2. Open "Settings"
3. Select "Network & Internet" or "Connections"
4. Select the Japan eSIM for mobile data
5. If necessary, turn ON data roaming
6. Select "Tethering" or "Mobile Hotspot"
7. Turn ON Wi-Fi tethering
8. Check the network name and password
9. Select the network from your computer or tablet
10. Enter the password to connect

On Android, the names and locations of the settings may vary by manufacturer and model.

For devices like Samsung Galaxy, Google Pixel, and Xiaomi, the display may differ, so if you can't find it, try searching for "Tethering" or "Hotspot" in the settings menu.

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How Many GB Do I Need for Tethering?

The required data capacity varies greatly depending on the devices you connect and the usage content.

If you are only checking emails or doing simple web searches, the data usage is relatively low, but activities like watching videos, online meetings, and sending files consume a lot of data.

Actual data usage will vary based on video quality, apps, communication time, and file sizes.

Be sure to consider the data usage of Google Maps and social media used on your smartphone, and choose a plan with ample capacity.

For detailed estimates by usage, please refer to Estimated Data Usage.

Recommended Data Capacity by Travel Days

If you are only checking emails or doing web searches for a short time, around 5 GB should be sufficient.

On the other hand, if you are conducting online meetings daily or handling large files for work, it is recommended to choose a plan with 20 GB or more or an unlimited plan.

How Many GB Do I Need for a 3-Day Trip to Japan?

For a 3-day trip, if you use tethering for about 30 minutes a day for checking emails or web searches, around 3 to 5 GB should be sufficient.

If you conduct online meetings for 1 hour a day, depending on the video quality, you may consume several GB, so consider 5 to 10 GB or more.

If you also plan to watch videos or send/receive large files, 10 GB or more or an unlimited plan would be safer.

How Many GB Do I Need for a 7-Day Trip to Japan?

For a week-long trip using tethering, 5 to 10 GB is a manageable capacity for light use, while 10 to 20 GB is suitable for daily work use.

If you conduct video conferences daily, even 20 GB may not be enough.

Check the meeting duration and video quality in advance, and use hotel Wi-Fi as needed.

How Many GB Do I Need for a Stay of 2 Weeks or More?

For trips or business trips longer than 2 weeks, consider plans with 20 GB or more or unlimited plans.

In particular, data consumption increases with the following usage:

• Connecting a computer daily
• Conducting online meetings
• Watching videos
• Using cloud storage
• Uploading photos and videos
• Sharing the connection with multiple people

For long stays, check not only the capacity but also the usage period, speed limits, additional charges, and tethering limits.

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Is Tethering Unlimited with an Unlimited eSIM?

Even if a Japan eSIM is labeled as unlimited, it does not necessarily mean that tethering can be used completely without limits.

Some products may have conditions such as:

• There is a limit on daily high-speed data capacity
• Speed decreases after exceeding a certain amount
• Heavy usage in a short period may lead to restrictions
• Tethering may have a separate data limit
• Communication speed may be adjusted during peak times
• Video streaming speed may be limited

Do not make judgments based solely on the label "unlimited"; check the terms of use and notes.

If you are using it for online meetings or work, the communication speed during low-speed periods is also important.

Reasons Why Data Capacity May Decrease During Tethering

Automatic Updates on Computers

Computers may automatically download update files for the OS or apps.

Large updates can consume several GB, so it is advisable to pause automatic updates while traveling.

Cloud Service Synchronization

If services like Google Drive, OneDrive, Dropbox, or iCloud sync automatically, a large number of files may be sent and received.

It is recommended to stop synchronization during tethering and perform it when connected to hotel Wi-Fi.

Backup of Photos and Videos

If photos from your smartphone or computer are automatically uploaded to the cloud, it can consume a large amount of data in a short time.

High-Quality Video Playback

On a computer, videos may automatically play at a higher quality than on a smartphone.

Setting the video service to a lower quality can help reduce data usage.

Simultaneous Connection of Multiple Devices

Connecting multiple devices simultaneously can lead to background communication on each device.

Disconnect any devices that are not in use from the tethering.

Ways to Save on Data Usage During Tethering

1. Stop automatic updates on the computer
2. Stop automatic synchronization of cloud storage
3. Only back up photos and videos when connected to Wi-Fi
4. Lower the video quality
5. Reduce background effects during video conferences
6. Turn off the camera if not needed
7. Close unused apps
8. Disconnect unused devices
9. Set the computer to a metered connection
10. Use hotel Wi-Fi when available

Turn Off the Camera During Video Conferences

In online meetings, turning off the video and using audio only can significantly reduce data consumption.

Set Up a Metered Connection

On Windows and other systems, you can set the connected network as a metered connection.

This setting can help reduce background updates and some automatic downloads.

Turn Off Tethering After Use

After finishing work on the computer, please turn off tethering on your smartphone.

Leaving it connected may consume data due to background communication.

Points to Note When Using Tethering

Smartphone Battery Consumption

During tethering, both mobile communication and Wi-Fi functions are used simultaneously, which increases battery consumption.

If using for long periods, prepare a mobile battery or charger.

Smartphone May Overheat

Long periods of tethering or heavy data usage may cause the smartphone to heat up.

Avoid direct sunlight and remove the case to allow heat to escape.

If it becomes very hot, stop tethering for a while.

Communication Speed May Decrease

Communication speed may decrease due to signal conditions, busy times, number of connections, and data limits.

Before important online meetings, check the communication speed and connection status.

Set a Password

Set a password for the tethering Wi-Fi that is hard to guess.

If you do not set a password, unauthorized users may connect, consuming your data or causing security issues.

Do Not Connect Too Many Devices

Connecting multiple devices simultaneously can reduce communication speed and increase data and battery consumption.

Only connect the necessary devices.

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How to Check if Tethering is Not Working

If mobile communication is possible with the Japan eSIM but tethering is not available, please check the following items:

1. Check if the purchased Japan eSIM supports tethering
2. Turn ON the Japan eSIM line
3. Select the Japan eSIM for mobile data
4. Turn ON data roaming for the Japan eSIM
5. Turn the tethering function OFF and then ON again
6. Restart the Wi-Fi on the device you are connecting
7. Check the Wi-Fi password
8. Restart the smartphone
9. If necessary, check the APN settings

Some products may require input for "Internet Sharing" or tethering-related items in the APN.

If it still does not work after checking the settings, please contact Japan eSIM Support.

If the Japan eSIM Itself is Not Connecting

If you cannot connect to the internet even on your smartphone, you need to check the eSIM line settings rather than tethering.

• Is the eSIM line ON?
• Is the Japan eSIM selected for mobile data?
• Is data roaming ON?
• Is the APN set correctly?
• Is network selection set to automatic?
• Have you toggled airplane mode ON and OFF?
• Have you restarted the device?

Even if you cannot connect, do not delete the eSIM immediately based on your own judgment.

Once deleted, you may not be able to reinstall it using the same QR code.

For detailed troubleshooting, please refer to Troubleshooting When Japan eSIM is Not Connecting.

Which is Better: Tethering or Rental Wi-Fi?

If you are using a computer alone for a short time, Japan eSIM tethering is convenient.

If multiple people need to share a connection for a long time or you want to avoid battery consumption on your smartphone, rental Wi-Fi is also a viable option.

Who Should Use Japan eSIM for Tethering?

• Those who want to use a computer or tablet while traveling
• Those who do not want to carry rental Wi-Fi
• Those who do not want to pick up and return devices at the airport
• Those who want to work for a short time
• Those who want to share a connection with one or a few people
• Those who want to prepare their communication environment before traveling

Who Should Consider Rental Wi-Fi?

• Those who will share with multiple people for a long time
• Those who will use large amounts of data on a computer daily
• Those who want to avoid battery consumption on their smartphone
• Those whose devices do not support eSIM
• Those who want to use dedicated communication equipment

How to Prepare Japan eSIM Before Traveling

If you want to use tethering immediately upon arrival in Japan, it is advisable to purchase the eSIM and complete the installation before your trip.

1. Check if your smartphone supports eSIM
2. Check if the SIM lock is removed
3. Choose a product that supports tethering
4. Decide on the necessary days and data capacity
5. Purchase the Japan eSIM online
6. Install the eSIM in a stable Wi-Fi environment
7. Activate the Japan eSIM after arriving in Japan
8. Confirm that the smartphone can connect
9. Turn ON tethering and perform a connection test

For information on compatible devices, please check List of eSIM-Compatible Devices.

For installation methods, detailed instructions can be found in the eSIM Setup Guide.

Frequently Asked Questions About Tethering

Can I use tethering with a data-only eSIM?

If it is a product that supports tethering, you can use it with a data-only eSIM.

Please check the usage conditions on the product page before purchasing.

Will there be additional charges for using tethering?

In most products, you can use tethering within the purchased data capacity.

However, some products may have specific limits or additional conditions for tethering.

How many GB do I need for tethering in a day?

If you are only checking emails or doing web searches, you may be able to use it within 500 MB a day.

If you are conducting online meetings or watching videos, you may consume 1 to 3 GB or more in a day.

Is 10 GB enough for a week?

If your usage mainly consists of short web searches and emails, 10 GB should be manageable.

If you conduct video conferences or watch videos daily, consider 20 GB or more or an unlimited plan.

Does an unlimited eSIM mean unlimited on the computer as well?

It varies by product. Check the tethering capacity, daily high-speed data limits, and speed restriction conditions.

How many devices can connect simultaneously?

The number of connectable devices varies by smartphone and product.

As the number of devices increases, the burden on speed and battery also increases, so only connect the necessary devices.

Can I use phone calls or LINE while tethering?

Usually, you can use them. However, tethering speed may temporarily decrease depending on the communication situation and device performance.

What should I do if my computer cannot connect?

Turn off the Wi-Fi on both the smartphone and the computer, then turn it back on.

Also, check the network name, password, number of connections, and the communication status of the eSIM.

Is USB tethering more stable?

It depends on the Wi-Fi environment and devices, but USB connections tend to be relatively stable and allow you to charge your smartphone while using it.

Will deleting and resetting the Japan eSIM fix the issue?

If you encounter connection troubles, do not delete the eSIM based on your own judgment.

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

For other questions, please refer to Frequently Asked Questions about eSIM.

Conclusion: Check Capacity and Usage Conditions When Using Tethering

By using a Japan eSIM that supports tethering, you can share your smartphone's communication with a computer or tablet even during your trip to Japan.

If you are only checking emails or doing simple web searches, small to medium capacity plans should be manageable.

On the other hand, online meetings, video streaming, and sending/receiving large files consume a lot of data even in a short time.

The data capacity guidelines for using tethering are as follows:

• Light use for 3 days: 3 to 5 GB
• Work use for 3 days: 5 to 10 GB
• Light use for 7 days: 5 to 10 GB
• Work use for 7 days: 10 to 20 GB
• Daily meetings and video use: Large capacity or unlimited

Even with unlimited plans, there may be tethering limits and speed restrictions. Please check the usage conditions before purchasing.

You can check products that fit your travel days and usage purposes at Japan eSIM Products and Pricing Plans.

For information on how to choose a Japan eSIM and basic usage methods, please also refer to Complete Guide to Japan eSIM.