What do I do if I run out of data on my eSIM while traveling in Japan?

While traveling in Japan, using Google Maps, social media, videos, tethering, and other services can sometimes lead to running out of eSIM data earlier than planned.

When you run low on data, you might wonder, "Can I add more data?" "Do I need to buy a new eSIM?" "Is it okay to delete the current eSIM?" Many people may be confused.

In conclusion, if your eSIM data runs out, first check the remaining balance and expiration date, and consider adding more data or purchasing a new Japanese eSIM.

However, the methods for adding data or extending the service may vary depending on the eSIM product. Additionally, the reason for not being able to connect may not be due to data exhaustion, but rather due to settings or signal conditions.

This article explains how to check your eSIM data balance during your trip to Japan, how to add data, switch to a new eSIM, and ways to save data usage.

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First, check your data balance

Even if you can no longer connect to the internet, it does not necessarily mean you have exhausted your data.

First, please check the data balance and expiration date of the eSIM you purchased.

The main ways to check your balance are as follows:

• Check the My Page of the eSIM provider
• Open the balance check page provided at the time of purchase
• Check the balance using a dedicated app
• Check the purchase confirmation email
• Check the mobile data usage on your smartphone
• Contact support

There may be discrepancies between the usage displayed on your smartphone and the balance on the eSIM service side.

The final data balance should be based on the management screen of the eSIM service you purchased or the support information.

It may be an expiration issue, not a data shortage

Even if you have data remaining, you will not be able to connect if the eSIM's expiration date has passed.

The validity period of a travel eSIM is mainly counted in the following ways:

• Starts from the moment you first connect to the network in Japan
• Starts from the moment the eSIM is installed
• Starts from the specified start date
• Starts or ends a certain period after the purchase date
• Ends based on Japan time or another time zone

Even with a "5-day plan," there are products that allow 120 hours of use and those that end on a date basis.

Check the usage start conditions and expiration date from the purchase confirmation email or product page.

What to do when you run out of data

The main options when you run out of data are the following four:

Method 1 | Add more data

If the eSIM you purchased supports additional charges, you can add data to your current eSIM.

You may be able to add data from the following places:

• My Page of the sales company
• Dedicated app
• Balance check page
• Purchase history
• Contacting support

If you can continue to use the same eSIM profile after adding, there is no need to scan a new QR code or switch lines.

However, some products do not support additional charges.

Please check the amount of data you can add, the fees, the reflection time, and the expiration date before making a purchase.

Things to check before adding data

• Is the current product compatible with charging?
• Is the expiration date still valid?
• What is the expiration date of the additional data?
• Will any settings need to be changed after adding?
• How long will it take for the charge to be reflected?
• Which is cheaper, the additional charge or a new purchase?

If you have a long remaining travel period, it may be easier to purchase a new high-capacity plan rather than repeatedly adding small amounts of data.

Method 2 | Extend the usage period

If you have data remaining but the expiration date is approaching, check if the product supports period extension.

For products that support period extension, you may be able to extend it from My Page or support.

However, some products cannot be extended after the expiration date has completely passed.

If you have decided to extend your stay or change your return flight, check before the expiration date.

Method 3 | Purchase a new Japanese eSIM

If you cannot add data or extend the period, you will need to purchase a new Japanese eSIM.

Since eSIMs can be purchased online, you can add one while in Japan using hotel or airport Wi-Fi.

The general flow is as follows:

1. Connect to a reliable Wi-Fi
2. Check the remaining travel days and required capacity
3. Purchase a new Japanese eSIM
4. Receive the QR code and setup information via email
5. Add the new eSIM to your smartphone
6. Rename the line to something recognizable
7. Select the new eSIM for mobile data communication
8. Turn on data roaming for the new eSIM if necessary
9. Turn off Wi-Fi and check the connection

You can check the products and plans available based on the remaining capacity and days at Japanese eSIM products and pricing plans.

If you want to compare plans, please also check Japanese eSIM pricing and plan comparison.

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Can I delete the old eSIM before adding a new one?

You do not need to immediately delete the current eSIM to add a new one.

If your smartphone has enough capacity for eSIMs, you can add a new eSIM while keeping the old one.

Keeping the old eSIM can be helpful if you have a little data left or if you need to verify something with support.

The QR code for a travel eSIM may only be usable once.

If you delete it, you may not be able to reinstall it with the same QR code, so do not delete it until you confirm the end of use.

Turn off the old eSIM instead of deleting it

If you are not using the old eSIM, simply turning off the line is sufficient.

After confirming the connection of the new eSIM, you can delete unnecessary profiles after your trip.

How to switch to the new eSIM

For iPhone

1. Open "Settings"
2. Select "Cellular"
3. Turn on the newly added Japanese eSIM
4. Select "Cellular Data"
5. Select the new Japanese eSIM
6. Turn off "Allow Cellular Data Switching"
7. Turn on data roaming for the new eSIM if necessary

For Android

1. Open "Settings"
2. Select "Network & Internet" or "Connections"
3. Select "SIM" or "SIM Manager"
4. Turn on the new Japanese eSIM
5. Select the new eSIM for mobile data
6. Turn off automatic data switching
7. Turn on data roaming for the new eSIM if necessary

The names of the settings may vary depending on the device and OS.

For detailed setup instructions, please check the eSIM setup guide.

How to choose the capacity when purchasing a new eSIM

Choose the additional capacity based on the remaining travel days and usage purpose.

Light usage refers to primarily using Google Maps, transit directions, text messaging, and simple web searches.

If you plan to post photos on social media, make voice calls, watch videos, or use tethering, choose a capacity that allows for some extra room.

For estimated data usage by purpose, please check data usage estimates.

Method 4 | Temporarily use free Wi-Fi

After exhausting your eSIM data, you will need an internet connection to purchase a new plan.

If you cannot connect, you may be able to use Wi-Fi from places such as:

• Hotels and accommodations
• Airports
• Train stations
• Cafes and restaurants
• Shopping malls
• Tourist information centers

Once connected to free Wi-Fi, complete the purchase of the new eSIM, receive the QR code, and finish the setup.

However, be cautious when entering credit card information or personal details on public Wi-Fi.

If possible, use Wi-Fi from sources that can be verified, such as hotels.

What happens when you run out of data?

The behavior after exhausting data capacity varies by eSIM product.

• You will be unable to connect to the internet
• It may switch to low-speed communication
• Only some services may be available
• You may only be able to access the additional charge screen
• High-speed data capacity may be restored the next day

For products with daily high-speed data limits, if you exhaust the capacity for that day, speed restrictions may apply, and it may be restored the next day.

On the other hand, for total capacity products, you may be unable to connect even if the usage period remains after exhausting the purchased capacity.

Slow communication does not necessarily mean you are out of data

If the communication speed slows down, the following reasons may also be considered:

• You have exhausted high-speed data capacity and are under speed restrictions
• The station or tourist spot is crowded
• Weak signal in underground or indoor areas
• Communication disruptions are occurring
• Your smartphone is connected to a different network
• APN or roaming settings are incorrect

If moving to a different location, toggling airplane mode on and off, or restarting the device does not improve the situation, please check the balance and speed restrictions.

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Ways to save remaining data capacity

If your data capacity is low but you can still connect, change your settings to reduce consumption.

Avoid watching videos

Videos on YouTube, Netflix, TikTok, Instagram Reels, etc., consume a lot of data.

Watch long videos using hotel Wi-Fi, and set the quality to low during mobile data usage.

Turn off auto-play for SNS videos

Stopping auto-play for videos in social media apps can reduce data usage that occurs just by scrolling through the screen.

Turn off automatic backup for photos and videos

Stop mobile data backups for Google Photos, iCloud, OneDrive, etc.

Stop automatic updates for apps

Turn off automatic updates via mobile data in the App Store or Google Play.

Use offline maps

Download maps of the areas you will visit using hotel Wi-Fi to reduce data usage while moving around.

Turn on low data mode

Using low data mode on iPhone or data saver on Android can help reduce background data usage.

Turn off tethering

Connecting a computer or tablet can consume a lot of data due to OS updates or cloud synchronization.

Please turn off tethering when not in use.

Turn off mobile data for unnecessary apps

From your smartphone settings, stop mobile data for apps you won't use during your trip.

How to check which apps are using data

For iPhone

1. Open "Settings"
2. Select "Cellular"
3. Check data usage by app
4. Turn off mobile data for unnecessary apps

If the statistics period has continued from before your trip, it may be difficult to accurately check usage during your trip.

Resetting the statistics before departure can make it easier to check.

For Android

1. Open "Settings"
2. Select "Network & Internet" or "Connections"
3. Select "Data Usage"
4. Check usage by app
5. Limit background data if necessary

If you still cannot connect after adding data

If you have added data or purchased a new eSIM but still cannot connect, please check your settings.

• Is the new eSIM line turned ON?
• Is the new eSIM selected for mobile data?
• Is data roaming turned ON if necessary?
• Is the APN set correctly?
• Is the old eSIM not selected for the data line?
• Is automatic data switching turned OFF?
• Are you meeting the usage start conditions of the purchased plan?

After checking the settings, turn off Wi-Fi and see if you can open websites or Google Maps using only the new eSIM.

Even if you cannot connect, do not delete the new eSIM immediately.

For detailed troubleshooting, please refer to troubleshooting when the Japanese eSIM cannot connect.

Information needed when contacting support

If you do not know your balance or how to add data, contact the support for the eSIM you purchased.

Having the following information ready can help expedite the process:

• Order number
• Email address used at the time of purchase
• Name of the purchased product
• Usage start date
• Smartphone model name
• Current location
• Displayed error messages
• Screenshot of mobile data settings
• Screenshot of the balance check screen

For support information, please check Japanese eSIM support.

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Choosing a plan to avoid running out of data next time

When determining the necessary capacity before your trip, check not only the number of travel days but also the apps you will use.

If you plan to use videos or tethering, it is safer to choose a capacity that is slightly higher than expected.

If you can use hotel Wi-Fi, you can save eSIM capacity by backing up photos or watching videos while connected to Wi-Fi.

Frequently Asked Questions about eSIM Data Shortages

Will the eSIM stop working if I run out of data?

It varies by product. Some products stop communication, while others switch to low-speed communication.

Can I add data to the same eSIM?

It is possible if the product supports additional charges. Please check from My Page or support.

What should I do if I cannot add data?

Purchase a new Japanese eSIM and switch the mobile data line to the new eSIM.

Should I delete the old eSIM before buying a new one?

Generally, there is no need to delete it. Turn off the old eSIM and confirm the connection of the new eSIM before organizing them.

Can I purchase a new eSIM while staying in Japan?

You can purchase online products even while staying in Japan.

Since you need an internet connection for purchase and setup, please connect to Wi-Fi at a hotel or similar location.

Why can't I connect even though I have data remaining?

There may be issues with the expiration date, APN, data roaming, mobile data line, or signal conditions.

Is it possible for data capacity to recover the next day?

For products with daily high-speed data limits, high-speed communication may be restored the next day.

The recovery time and reference time zone vary by product.

Can I use the additional data immediately?

It may be reflected immediately, but some products may take time to reflect.

Please check the additional purchase confirmation email or My Page.

Is it necessary to restart my smartphone after adding data?

It is not mandatory, but if the additional data is not reflected, toggling airplane mode on and off or restarting the device may help.

Will I not run out of capacity with an unlimited eSIM?

Even with unlimited plans, there may be daily high-speed data limits or speed restrictions due to fair usage.

Please check the usage conditions before purchasing.

For other questions, please refer to frequently asked questions about eSIM.

Summary | Check your balance and either add data or purchase a new eSIM

If you run out of eSIM data during your trip to Japan, first check your data balance and expiration date.

If you have exhausted your data, you can respond in the following ways:

• Add data to your current eSIM
• Extend the usage period
• Purchase a new Japanese eSIM
• Temporarily use free Wi-Fi until you purchase and set up

Even if additional charges are not supported, you can continue your trip by purchasing a new eSIM online and switching the mobile data line.

When adding a new eSIM, do not delete the old one immediately; instead, turn off the line and keep it for reference.

If your remaining data capacity is low, you can save data by stopping video viewing, cloud backups, automatic updates, and tethering.

You can check the plans that match your additional required days and capacity at Japanese eSIM products and pricing plans.