If you plan to use eSIM during your trip to Japan, you may be wondering whether to set it up before departure or after arriving in Japan.
Basically, it is recommended to install the eSIM before departure and activate the communication line after arriving in Japan.
By preparing in advance, you won't have to search for a QR code or secure a Wi-Fi connection after arriving at the airport in Japan. After arrival, you can easily use map apps, transit guides, translation apps, and more with just a simple setup.
In this article, we will clearly explain the recommended timing for setting up Japan eSIM, the operations to perform before departure and after arrival, and important points regarding the start date of use. If you want to check the basic information about Japan eSIM first, please also refer to the Complete Guide to Japan eSIM.
Recommended Timing for Setting Up Japan eSIM
Setting up Japan eSIM is smooth when divided into the following two stages.
- Before Departure: Install eSIM on your smartphone
- After Arriving in Japan: Activate the eSIM line and start communication
Installing eSIM may require an internet connection. Therefore, it is advisable to set it up in advance at a location where you can use stable Wi-Fi, such as at home or in a hotel.
However, depending on the eSIM product, the usage period may start from the time of installation or from the time you connect to the line. Be sure to check the usage start conditions and expiration date before purchasing.
If you want to compare plans available in Japan, please check Comparison of Japan eSIM Prices and Plans.
Preparing Japan eSIM Before Departure
1. Check if your smartphone supports eSIM
First, check if the smartphone you will be using supports eSIM.
Many devices, such as iPhone, Google Pixel, and Samsung Galaxy, support eSIM, but the compatibility may vary depending on the country of sale and the carrier, even for the same model.
Also, if your device is SIM-locked, you may not be able to use an overseas eSIM. Before purchasing, please check the list of eSIM-compatible devices and the status of SIM locking.
2. Purchase an eSIM plan suitable for your trip
Next, choose a Japan eSIM that fits your travel duration and purpose.
The required data capacity differs between using maps and messaging versus watching videos and tethering.
If you are unsure about the required data capacity, please refer to the Estimated Data Usage. You can check the plans for traveling to Japan on the Japan eSIM product page.
3. Add eSIM using QR code or manual input
When you purchase eSIM, you will typically receive a QR code or setup information via email.
From your smartphone's settings screen, select "Add eSIM" or "Add Mobile Data Plan" and scan the QR code.
For detailed operation methods for each device, please refer to the eSIM Setup Guide.
4. Keep the Japan eSIM line off before departure
After installing the eSIM, it is advisable not to use the Japan eSIM for mobile data communication immediately and to keep the line off.
Maintain your usual SIM as the main line and activate the Japan eSIM after arriving in Japan.
To avoid accidentally starting roaming communication outside Japan, also keep the data roaming for the Japan eSIM off until necessary.
Settings to Perform After Arriving in Japan
1. Turn on the Japan eSIM line
Once you arrive in Japan, open your smartphone's mobile data settings and turn on the Japan eSIM line that you added earlier.
If multiple SIMs are displayed, it can be helpful to set a clear name like "Japan eSIM" or "Travel" to avoid confusion.
2. Select Japan eSIM for mobile data communication
Select Japan eSIM as the line to use for mobile data communication.
If the overseas roaming for your usual SIM is turned on, you may incur unintended communication charges. It is advisable to turn off the data roaming for your usual SIM during your stay in Japan.
3. Turn on data roaming for Japan eSIM
For some travel eSIM products, it is necessary to turn on data roaming to communicate within Japan.
Open the line settings for Japan eSIM and turn on data roaming as needed.
4. Disable airplane mode and check the connection
Disable airplane mode and check if communication indicators like "4G," "LTE," or "5G" appear at the top of the screen.
Open a web page in a browser or launch a map app to confirm that you can connect to the internet properly.
Can I install eSIM after arriving in Japan?
It is also possible to install eSIM after arriving in Japan.
However, installation requires a stable internet environment. Free Wi-Fi at the airport may become unstable due to congestion or authentication procedures.
Additionally, if you display the QR code on the same smartphone, you may not be able to scan it with that device's camera. In that case, you will need to display the QR code on another device or use the information for manual input.
If you want to communicate immediately after arrival, it is recommended to complete the installation before departure.
When does the usage period for eSIM start?
The timing for starting to use Japan eSIM varies by product.
The main start conditions include the following:
- When the eSIM is installed on the smartphone
- When you first connect to a compatible network in Japan
- The usage start date specified at the time of purchase
- When the eSIM is activated
If you are worried that "installing before departure will reduce the usage period," please check the product description and the setup instructions you receive after purchase.
If you are unsure about the usage start conditions, it is advisable to inquire through Japan eSIM Setup and Support Information before setting up.
Points to Note When Setting Up Japan eSIM
QR codes may only be usable once
The eSIM QR code may only be registered to one device in principle.
If you delete the eSIM after installation, you may not be able to reinstall it using the same QR code. Please do not delete the eSIM from the device until the end of use.
Do not delete the original SIM until communication is established
You do not need to delete your usual SIM to use Japan eSIM.
If your device supports dual SIM, you can keep both your original SIM and Japan eSIM at the same time. It is also possible to receive SMS on your original phone number while switching mobile data communication to Japan eSIM.
Check if it is a number plan or data-only plan
Many travel eSIMs are data-only and do not include a Japanese phone number or regular voice calls.
If you need a phone number, please check the eSIM plan with phone number.
How to Check if Japan eSIM is Not Connecting
If Japan eSIM is not connecting after your arrival, please check the following items.
- Is the Japan eSIM line turned on?
- Is Japan eSIM selected for mobile data communication?
- Is data roaming turned on?
- Is airplane mode disabled?
- If APN settings are required, are they entered correctly?
- Have you restarted your smartphone?
If you are temporarily unable to connect to the network, turning airplane mode on for a moment and then off after a few seconds may improve the situation.
For detailed confirmation procedures, please refer to How to Troubleshoot When Japan eSIM is Not Connecting. You can also check frequently asked questions at Frequently Asked Questions about eSIM.
Frequently Asked Questions About the Timing of Setting Up Japan eSIM
How many days before my trip should I purchase Japan eSIM?
You can purchase it just before departure, but considering the time needed to check device compatibility and setup, it is advisable to prepare a few days in advance.
Is it okay to install eSIM before departure?
For many products, it is possible to install before departure. However, since the usage period may start from the time of installation for some products, please check the usage start conditions.
Is it okay to turn on data roaming before arriving in Japan?
To prevent unintended communication, it is recommended to turn on data roaming for Japan eSIM after arriving in Japan.
Can I use my original SIM after setting up eSIM?
If your device supports dual SIM, you can use both your original SIM and eSIM simultaneously. You can also separate usage by using your original SIM for calls and SMS while using Japan eSIM for data communication.
What should I do if I cannot communicate immediately after arriving in Japan?
Check the line selection, data roaming, APN settings, and restart your device. If the issue persists, please contact support.
Conclusion: It is Recommended to Install Before Departure and Activate the Line After Arriving in Japan
To use Japan eSIM smoothly, it is recommended to install eSIM in a stable Wi-Fi environment before departure and activate the line and data roaming after arriving in Japan.
By completing the setup in advance, you can immediately use maps, transit guides, translation, messaging, and more upon arrival in Japan.
However, since the timing for starting use varies by product, please check the usage conditions before purchasing or installing.
If you are looking for an eSIM that matches your travel duration and data usage in Japan, please check the Japan eSIM Products and Pricing Plans.
