Archives FAQs

Will I be charged extra for data usage?

🅰️ No. JB Voice SIM does not incur any additional data charges, whether you use it in Japan or overseas.

🗾 Use in Japan

📶 Mobile data service is available in Japan.
・You will receive high-speed data according to your subscribed plan（1GB–50GB）.
・After your high-speed data allowance is used up, your connection will not be disconnected. The speed will automatically be reduced to 200kbps, and you can continue using the internet.
💬 Examples:
LINE text messages, emails, and simple web browsing can still be used.

📢 Internet Settings in Japan
After arriving in Japan:
🍎 iPhone: You need to download the Configuration Profile.
🤖 Android: You need to configure the APN settings.

🌐 Overseas Roaming (Countries Outside Japan)

📞 Outside Japan, only the following services are available:
✅ Voice Calls and SMS
❌ Mobile data (internet access) is not available overseas.

Therefore:
・Whether mobile data is turned ON or OFF
・Whether you are connected to Wi-Fi or not

No international data roaming charges will occur.

📢 How to Use Overseas

After receiving the SIM card overseas:
Simply insert the SIM card into your smartphone to use voice calls and SMS.
❌ Do not download the Configuration Profile.
❌ Do not configure the APN settings.
This prevents your smartphone from attempting to establish mobile data communication.

How do I activate my eSIM?

A:
JB Voice eSIM activation will be processed between 10:30 AM and 6:30 PM (Japan Time).

After the activation process is completed, docomo will directly send the “Activate eSIM” notification to the device associated with the EID provided during your application.

When the “Activate eSIM” screen appears, please follow the instructions displayed on your device to complete the eSIM installation and activation.

【iPhone Example】
Open:
Settings ➡ Mobile Service (Cellular) ➡ Tap “Activate eSIM”

Then follow the on-screen instructions to complete the setup.

If the “Activate eSIM” screen does not appear automatically:

📩 Please check the eSIM activation email sent by JB Mobile.
📖 Follow the instructions in the operation manual included in the email to complete the eSIM installation and activation.

⚠️ Notes:
・Please use the device with the EID registered during your application.
・Please make sure your device is connected to Wi-Fi or mobile data to complete the eSIM activation process.

How can I update my credit card information?

Please follow the steps below to update your credit card information.

  1. Visit the JB Mobile homepage:
    https://jbmobile.jp/en/
  2. Log in to My Account.
  3. Select Stripe Billing Management from the left-side menu.
  4. Log in with your email address. You will be redirected to the Stripe page, where you can update your credit card information.

※ After the update is completed, the new credit card information will be used for future payments.

How can I delete a used Japanese eSIM?

🅰️If you accidentally delete the eSIM that is currently in use, you won’t be able to re-add it. Please be careful when performing the deletion. There is no issue if you choose not to delete it.

■ iPhone
➀Delete the Japanese eSIM 【Settings】➡【Mobile Services】➡【Select the Japanese eSIM label】➡【Delete eSIM】
②Activate the original SIM used 【Settings】➡【Mobile Services】➡【Select the original SIM label】➡ Turn on 【Enable this number】

■ Android
The operation method varies slightly depending on the brand.
※Samsung
【Settings】➡【Connections】➡【SIM card manager】➡ Select the eSIM to delete ➡ Delete
※Oppo
【Settings】➡【Mobile network】➡【eSIM】➡ Select the eSIM to delete ➡ Delete

Why am I unable to get a good signal even within the docomo service area?

【Reason 1】Even within the service area, poor signal reception can occur due to obstacles or radio interference. Try moving to a slightly different location and test again.

【Reason 2】If you are using multiple SIM cards or eSIMs at the same time, with all of them set to “on” and set to automatically switch mobile data, it may automatically switch to a SIM with poor signal reception, causing it to be unusable. It is recommended to set the mobile data to your company’s SIM and turn off the automatic switching feature. If you want to use a different SIM, manually switch the mobile data to that SIM.

Can I receive Taiwan SMS messages for free while in Japan?

Yes. You can receive Taiwan SMS messages (including verification codes) for free while in Japan.

📌 Explanation:
• Taiwan mobile numbers (such as Chunghwa Telecom / Taiwan Mobile) can still receive SMS messages while you are in Japan.
• Even without applying for international roaming, SMS reception usually works as long as the SIM card remains active.
• Receiving SMS messages generally does not incur any charges (actual conditions may vary depending on your mobile carrier).

📌 Dual SIM Settings (for both Android and iPhone):
• Keep both your original SIM (Taiwan number) and JB SIM enabled at the same time.
• For calls and SMS, we recommend keeping your original SIM (SIM1).
• Switch mobile data to the JB SIM (SIM2) for internet access.
• The same settings apply when using eSIM, allowing both SIMs to be used simultaneously.

📌 Recommendation:
• Switch mobile data to the JB SIM after arriving in Japan.
• This helps prevent accidental roaming charges from using mobile data on your original SIM.

How can I prevent my original SIM from being used for international roaming?

To avoid accidentally using your original SIM and incurring international roaming charges, please follow the settings below:

📌 Basic Settings
• Switch Mobile Data to the SIM/eSIM you use in Japan.
• Turn off the “Allow Mobile Data Switching” function.
• This prevents your device from automatically using your original SIM for internet access.

📌 SMS Information
• You can continue to receive Taiwan SMS messages normally (usually free of charge).
• SMS charges from other countries depend on the regulations of your original mobile carrier.

📌 To completely avoid roaming charges, you can turn off your original SIM:

【iOS Devices】
Settings → Cellular → Select your original SIM → Turn off “Turn On This Line”

【Android Devices】
Settings → Connections → SIM Card Manager → Select your original SIM → Turn off

📌 Recommendation
If you do not need to use your original phone number, we recommend turning off your original SIM completely to prevent any accidental roaming charges.

Can I use the SIM/eSIM again after leaving Japan and returning later?

Yes, you can.

As long as your SIM/eSIM is still within the validity period, you can continue using it when you re-enter Japan, even if you temporarily leave Japan.

📌 After returning to Japan:
• Turn on Mobile Data
• Switch Mobile Data to the JB SIM/eSIM
• Wait for your phone to reconnect to the Japanese mobile network

There is no need to apply again or reinstall the SIM/eSIM. It can be used normally as long as it remains within the validity period.

Free Wi-Fi Services at Japanese Airports

If you are unable to complete activation immediately after arriving in Japan, please connect to the airport’s free Wi-Fi first and contact our customer support. We will assist you in checking your settings and activation status.

• New Chitose Airport
https://www.new-chitose-airport.jp/ja/service/internet_fax_copy/lan/

• Hakodate Airport
https://www.airport.ne.jp/facility/wifi/

• Sendai Airport
https://www.sendai-airport.co.jp/service/wifi.html

• Narita International Airport
https://www.narita-airport.jp/jp/service/svc_33_wire

• Haneda Airport
https://tokyo-haneda.com/service/facilities/wireless_lan.html

• Chubu Centrair International Airport
https://www.centrair.jp/service/wireless-lan.html

• Kansai International Airport
https://www.kansai-airport.or.jp/service/internet/06.html

• Fukuoka Airport
https://www.fukuoka-airport.jp/service/wifi01.html

• Aso Kumamoto Airport
https://www.kumamoto-airport.co.jp/facilities/kumamoto-free-wi-fi/

• Naha Airport
https://www.naha-airport.co.jp/service/wifi/wifi-spot/

📌 Recommendation
Before departure, please save screenshots of our customer support contact information and your order details so that you can quickly receive assistance after arriving in Japan.