When people living abroad temporarily return to Japan, they may be confused about how to connect their smartphones.
"I want to use the internet as soon as I arrive at the airport." "Do I need a Japanese phone number or SMS?" "What GB do I need for a one-week temporary return?" Many people may have these questions.
For short stays, the Japanese eSIM that can be purchased and set up online is convenient. There is no need to receive or exchange a physical SIM card, and you can use Google Maps, transit guides, LINE, email, and more immediately after arriving in Japan.
However, when choosing an eSIM for a temporary return, it is necessary to check not only the duration of stay but also the data capacity, phone number, SMS, tethering, and whether it can be used in conjunction with the main line.
In this article, we will explain how to choose a Japanese eSIM recommended for temporary returns, based on the duration of stay and purpose of use.
Reasons Why Japanese eSIM is Recommended for Temporary Returns
The Japanese eSIM is a digital SIM that allows you to add a communication plan to your smartphone.
If your device is compatible, you can use Japanese mobile data without having to swap out a physical SIM card.
The main benefits of using a Japanese eSIM during a temporary return are as follows:
- Can be purchased online before arriving in Japan
- No need to pick up a SIM card at the airport
- Less likely to be lost since there is no physical SIM to exchange
- You may be able to keep your main line used overseas
- You can choose a short-term plan that fits your duration of stay
- No need to return it after your trip
It is especially suitable for those who want to contact family immediately after arriving at the airport or check train transfer information.
Main Communication Methods Available During Temporary Returns
The communication methods available during a temporary return include Japanese eSIM, prepaid SIM, rental Wi-Fi, and international roaming.
| Communication Method | Features | Suitable For |
|---|---|---|
| Japanese eSIM | Online purchase and setup, no SIM exchange required | Short stays, those who want to use it immediately after arrival |
| Prepaid SIM | Use by inserting a physical SIM into the device | Those using devices that do not support eSIM |
| Rental Wi-Fi | Carry a dedicated router | Those who want to share with family or multiple devices |
| International Roaming | Use the main line overseas as is | Those who want to keep the setup simple |
| Free Wi-Fi | Free use at compatible facilities | Those with low data usage |
For short temporary returns, the Japanese eSIM, which does not require pickup or return, is likely to be the easiest to use.
On the other hand, if you want to share the same connection with your entire family or use multiple devices, rental Wi-Fi may be a better fit.
How to Choose a Japanese eSIM for Temporary Returns
Select a Plan That Matches Your Duration of Stay
First, choose a validity period that matches the number of days of your temporary return.
If you choose a plan that is too short, there is a possibility that the usage period will expire before your return date.
Conversely, if you choose a plan that is unnecessarily long, the cost may be higher.
| Duration of Temporary Return | Easy-to-Choose Plan |
|---|---|
| 1-3 days | Short-term plan of about 3 days |
| 4-7 days | 5-day or 7-day plan |
| 8-14 days | 10-day or 15-day plan |
| 15-30 days | 30-day plan |
If there is a possibility of changing your return flight or extending your stay, it is advisable to choose a period with an extra 1-2 days of leeway.
Check the Required Data Capacity
The required data capacity varies depending on the duration of stay and how you use your smartphone.
If your main activities are maps, messaging, and web searches, you can manage with a small capacity.
If you plan to use video, video calls, or tethering, a larger capacity plan will be necessary.
| Usage Style | Daily Estimate | Main Uses |
|---|---|---|
| Light Use | About 300-500MB | Maps, transit guides, messaging |
| General Use | About 500MB-1GB | SNS, photo posting, searching, voice calls |
| Heavy Use | 1-3GB or more | Video, video calls, tethering |
For detailed data capacity estimates, please check data usage estimates.
Check if You Need a Phone Number and SMS
Most general travel eSIMs are data-only products and may not include a Japanese phone number or SMS functionality.
If you have the following needs, consider an eSIM with a phone number:
- I want to call stores or hospitals in Japan
- I want to receive calls from delivery services or real estate companies
- I need SMS verification for Japanese services
- I need a Japanese phone number for work
If you do not need a Japanese phone number and only plan to use LINE or WhatsApp, a data-only eSIM may be easier to use.
For plans with a phone number, please see eSIM with phone number.
Check if Tethering is Supported
If you plan to use a computer or tablet during your temporary return, choose an eSIM that supports tethering.
Some products may not allow tethering or may have limits on tethering capacity.
If you plan to use it for online meetings or work, also check the data capacity and speed limits.
Check the Timing for Starting Use
The timing for when the usage period for travel eSIMs begins varies by product.
- When you first connect to the Japanese network
- When the eSIM is installed
- On the specified start date
- After a certain period following purchase
Some products may start the usage period when installed before departure, so be sure to check before purchasing.
Check the Support System
For those who are not familiar with eSIM setup, it is recommended to choose a product that offers support in Japanese or a language that is easy to use.
It is reassuring to confirm the inquiry methods, support hours, and necessary information before purchasing.
For support, please check Japanese eSIM support.
Recommended Data Capacity for Temporary Returns by Duration of Stay
1-3 Days Temporary Return
For a short stay, if your main activities are moving from the airport to home, using Google Maps, and messaging, about 1-3GB is a good estimate.
If you plan to use a lot of video or video calls, consider 3-5GB or more.
5-7 Days Temporary Return
For a stay of about a week, 3-5GB is an easy capacity to choose.
If you use SNS, photo posting, and voice calls daily, having about 5-10GB is reassuring.
10-14 Days Temporary Return
For a stay of around two weeks, 5-10GB is a good estimate.
If your family home does not have Wi-Fi and you will rely solely on mobile data, consider 10-20GB or more.
15-30 Days Temporary Return
If you are staying for nearly a month, 10-20GB or an unlimited plan would be good options.
For those using it for work, video, online meetings, or tethering, a large capacity plan is recommended.
| Duration of Stay | Light Use | General Use | Video/Work Use |
|---|---|---|---|
| 1-3 days | About 1GB | 1-3GB | 3-5GB or more |
| 5-7 days | About 3GB | 3-5GB | 10GB or more |
| 10-14 days | About 5GB | 5-10GB | 10-20GB or more |
| 15-30 days | About 10GB | 10-20GB | Large capacity/unlimited |
You can check products by capacity and duration at Japanese eSIM pricing and plan comparison.
Is a Japanese Phone Number Necessary for Temporary Returns?
Whether you need a Japanese phone number depends on your plans during your temporary return.
Cases Where You Can Manage Without a Phone Number
- Contacting family and friends using LINE or WhatsApp
- Reservations are completed online
- No plans to make regular calls within Japan
- Not using SMS verification
- Staying for a short period
Cases Where an eSIM with a Phone Number is Recommended
- Planning to call hospitals or government offices
- Need SMS verification for banks or various services
- Receiving work-related calls
- Want to receive return calls from hotels or stores
- Want to register a Japanese phone number as a contact
Even with a data-only eSIM, you can use internet calls like LINE or WhatsApp.
However, if you need to make regular calls to Japanese landlines or mobile phones, a plan with a phone number is convenient.
Can You Use Your Overseas Main Line and Japanese eSIM Simultaneously?
If you have a dual SIM compatible smartphone, you can use your overseas main line and Japanese eSIM at the same time.
Here is a recommended way to differentiate usage:
| Usage | Line to Use |
|---|---|
| Maintain overseas phone number | Main line |
| SMS verification to overseas number | Main line |
| Data communication in Japan | Japanese eSIM |
| Google Maps/SNS | Japanese eSIM |
If you want to keep your main line, be sure to turn off data roaming on the main line to prevent unintended international roaming.
Select the Japanese eSIM for mobile data communication, and it is also advisable to turn off automatic switching of data lines.
For detailed settings, please refer to the article on dual SIM settings.
Pre-Check for Using Japanese eSIM During Temporary Returns
Is Your Smartphone Compatible with eSIM?
Not all smartphones are compatible with eSIM.
Even with the same model name, compatibility may vary depending on the country of sale and model.
Check the device you plan to use from the list of eSIM compatible devices.
Is the SIM Lock Released?
If your device is SIM locked, you may not be able to add another company's eSIM.
Check the SIM lock status from the carrier you purchased from or the device settings.
Do You Have Another Device to Display the QR Code?
If you received the QR code for eSIM setup on the same smartphone, you may not be able to scan it directly with the camera.
Display the QR code on a computer or tablet, or use the manual setup information.
Is There Stable Wi-Fi Available?
An internet connection is required to install the eSIM.
Set it up in a stable Wi-Fi environment, such as at home before departure or at the airport or hotel after arrival.
When to Set Up Japanese eSIM?
Basically, it is recommended to install the eSIM before departure and activate the line after arriving in Japan.
By setting it up before departure, you won't have to search for the QR code or spend time connecting to Wi-Fi after arriving at the airport.
The general flow is as follows:
- Purchase the Japanese eSIM before departure
- Check the conditions for starting use
- Connect to a stable Wi-Fi
- Scan the QR code to add the eSIM
- Change the line name to "Japanese eSIM" or similar
- Keep the line OFF until arrival in Japan
- Turn ON the Japanese eSIM after arrival
- Select the Japanese eSIM for mobile data communication
- Turn ON data roaming if necessary
Some products may start the usage period at the time of installation.
Be sure to check the conditions for starting use of the product you purchased.
For detailed setup instructions, please refer to the eSIM setup guide.
Settings to Check After Arriving in Japan
After arriving in Japan, check the following settings:
- Turn ON the Japanese eSIM line
- Select the Japanese eSIM for mobile data communication
- Set data roaming according to the product instructions
- Turn OFF data roaming on the main line
- Turn OFF automatic switching of mobile data
- Turn OFF Wi-Fi and check the connection
If Google Maps and websites open, the basic connection is complete.
How to Save Data Capacity During Temporary Returns
Use Wi-Fi at Home or Hotels
You can save data capacity by performing tasks like watching videos, backing up photos, and updating apps while connected to Wi-Fi.
Turn OFF Automatic Backup for Photos and Videos
If automatic backup for iCloud or Google Photos is ON, it may consume a lot of data.
Lower the Video Quality
Video services like YouTube and Netflix can vary greatly in data consumption depending on the video quality.
When using mobile data, set it to low or standard quality.
Turn OFF Auto-Play for SNS Videos
Videos on platforms like Instagram and TikTok can consume data quickly due to continuous playback, even for a short time.
Use Offline Maps
If you download maps for areas you plan to visit while connected to Wi-Fi, you can reduce data usage while on the move.
Avoid Excessive Tethering
Connecting a computer can consume a large amount of data due to OS updates or cloud synchronization.
If the eSIM Doesn't Connect During Temporary Returns
If you cannot connect with the Japanese eSIM after arriving in Japan, please check the following items:
- Is the Japanese eSIM line ON?
- Is the Japanese eSIM selected for mobile data communication?
- Is data roaming ON if necessary?
- Is the APN set correctly?
- Is it the start date for use?
- Is there remaining data capacity?
- Is the device SIM locked?
- Is the network selection set to automatic?
After checking the settings, try turning ON airplane mode and then turning it OFF, or restart your smartphone.
Even if you cannot connect, do not delete the eSIM immediately on your own judgment.
You may not be able to reuse the QR code, and it may become impossible to reinstall the same eSIM.
For detailed troubleshooting methods, please check troubleshooting for when the Japanese eSIM doesn't connect.
Important Points to Check for Japanese eSIM for Temporary Returns
Unlimited Plans May Have Speed Limits
Even products labeled as unlimited may have daily high-speed data limits or speed restrictions due to fair use.
If you plan to use video or tethering, please check the restriction conditions.
Data-Only eSIM Cannot Make Regular Calls
With a data-only eSIM, you cannot make regular calls to Japanese phone numbers from the phone app.
If you need to make calls, choose a plan with a phone number or use a calling app.
Deleting the eSIM May Prevent Reuse
The QR code for travel eSIM may only be usable once.
If you encounter setup issues, do not delete it before confirming with support.
Be Cautious of Roaming Charges on the Main Line
If you keep your overseas main line ON, please turn OFF data roaming.
There may be additional charges for calls and SMS.
Check How the Usage Period is Calculated
Some products calculate usage days on a 24-hour basis, while others calculate by date.
If you need communication on the return date, allow for some leeway in the expiration date.
Who Should Consider Japanese eSIM for Temporary Returns?
- Those who want to use the internet immediately after arriving in Japan
- Those who are staying for a short period of a few days to a month
- Those who do not want to pick up a SIM card at the airport
- Those who want to keep their overseas main line
- Those who frequently use Google Maps or transit guides
- Those who communicate via LINE or WhatsApp
- Those who do not want to carry rental Wi-Fi
Who Might Be Better Suited for Other Communication Methods?
- Those whose devices do not support eSIM
- Those who want to share communication with the whole family
- Those who want to keep multiple smartphones or computers connected at all times
- Those who must have a Japanese phone number or SMS
- Those who find eSIM setup difficult
In this case, consider comparing prepaid SIMs, rental Wi-Fi, and eSIMs with phone numbers.
Frequently Asked Questions About Japanese eSIM for Temporary Returns
Can I Purchase a Japanese eSIM for a Temporary Return?
If you have a compatible device and internet access, you can purchase it online from abroad.
Is it Okay to Purchase After Arriving in Japan?
You can purchase it, but you will need Wi-Fi for the purchase and setup.
If you want to use it immediately after arriving at the airport, it is safer to prepare it before departure.
How Many GB Do I Need for a One-Week Temporary Return?
If your main activities are maps, messaging, and SNS, about 3-5GB is a good estimate.
If you plan to use video or video calls, consider 5-10GB or more.
Does it Come with a Japanese Phone Number?
Most general travel eSIMs are data-only and do not come with a Japanese phone number.
If you need a phone number, choose a plan with a phone number.
Can I Use It Simultaneously with an Overseas SIM?
If you have a dual SIM compatible device, you may be able to use your overseas main line and Japanese eSIM at the same time.
Is it Okay to Keep the Main Line ON?
If you set mobile data communication to the Japanese eSIM and turn OFF data roaming on the main line, it will be easier to use both.
However, please check with your carrier for call and SMS charges.
Can I Use LINE with Japanese eSIM?
If you can connect to the internet, you can use messaging, voice calls, and video calls.
Will My Overseas Phone Number Disappear When I Set Up the eSIM?
Typically, adding a Japanese eSIM will not delete your overseas main line.
However, please check the dual SIM compatibility of your device.
Can I Delete the eSIM After My Temporary Return?
You can delete it after confirming the end of use and reconnecting to your main line.
If there is still validity left or you are checking with support, keep it OFF instead of deleting it.
What Should I Do If I Run Out of Data Capacity?
If additional charges are supported, you can add capacity.
If not supported, you will need to purchase a new Japanese eSIM and switch data lines.
Can I Use an Unlimited Plan Without Worry?
Even with an unlimited plan, there may be high-speed data limits or speed restrictions.
Please check the usage conditions before purchasing.
For other questions, please see frequently asked questions about eSIM.
Conclusion: Choose a Japanese eSIM That Fits Your Duration and Purpose for Temporary Returns
For temporary returns, the Japanese eSIM, which can be purchased and set up online without the need for pickup or return at the airport, is convenient.
When choosing, please check the following items:
- Validity period that matches the duration of your temporary return
- Data capacity needed for maps, SNS, videos, etc.
- Whether you need a Japanese phone number or SMS
- Whether it supports tethering
- Timing for starting use
- Support system
For a typical one-week temporary return, about 3-5GB is a good estimate. If you plan to use a lot of video or video calls, consider 5-10GB or more.
If you want to keep your overseas main line, turn OFF data roaming on the main line and set the Japanese eSIM for mobile data communication.
You can check currently available short-term plans at Japanese eSIM products and pricing plans.
If you want to compare capacity and usage periods, please see Japanese eSIM pricing and plan comparison.
