Archives FAQs

Data eSIM Activation Guide

Q1：Do I need to issue the QR Code immediately after receiving the Activation URL?

A: ❌ No, you do not need to issue it immediately.
🕒 Newly applied eSIMs have a 45-day QR Code issuance period.

Recommendation:
✅ Issue the QR Code before departure.
✅ This prevents the usage period from starting early due to flight changes, typhoons, or trip cancellations.

Q2：What does “Complete operation within 44 days, automatically activated on the 45th day” mean?

A:
This means:

📌 The Activation URL operation period before pressing “Issue”.
⏰ Please complete QR Code issuance within 45 days after receiving the Activation URL.
⚠️ If the QR Code is not issued after 45 days:
➡️ The system will automatically start counting the usage period.
➡️ The countdown will begin even if you are outside Japan.

Q3：Will the usage period start immediately after pressing “Issue”?

A: ❌ No.
Pressing “Issue” only generates the QR Code.
The usage period does not start immediately after issuance.
The following steps must be completed:
1️⃣ QR Code issuance
2️⃣ eSIM installation
3️⃣ Arrival in Japan
4️⃣ Smartphone connects to the docomo network
➡️ The eSIM will then be officially activated and the usage period will begin.

Q4：How is the usage period calculated?

A:
After eSIM activation:
🇯🇵 The usage period is calculated based on Japan Standard Time (JST) calendar days.
Example:
📅 7/14: Issue and install eSIM in Taiwan
📅 7/15: Arrive in Japan and connect to the docomo network, will be counted as Day 1.

Q5：Can I issue the QR Code during system maintenance?

A: System maintenance time: Every Tuesday 22:00～Every Wednesday 09:00 is the system maintenance period.
✅ Please complete QR Code issuance before Tuesday 22:00.
⚠️ If you operate during maintenance:
・The status may remain pending.
・The QR Code will be issued after maintenance is completed.

Q6：Do I need to keep the page open after pressing “Issue”?

A: ❌ No.
After pressing “Issue”:
✅ You may close the page.
✅ Open the Activation URL again later to check the result.
📌 You can check:
・QR Code issuance status
・Activation start/end dates
・Remaining data / used data capacity

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:
After your passport verification and address verification are completed, your eSIM will be activated on the same day or the following day.
Once activation is complete, your smartphone will automatically display the “Activate eSIM” screen. Please follow the instructions on your phone to complete:
eSIM installation and activation

If the “Activate eSIM” screen does not appear automatically:
📩 Please check the eSIM activation email sent by JB Mobile.
📖 Follow the operation manual to complete eSIM installation and activation.

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.