FAQ

eSIM

Compatibility & Setup

Is my device eSIM-compatible?

eSIMs are compatible with any device with a 32-digit EID. That's most newer smartphones, including iPhones and the most recent Android devices. To find your device's 32-digit EID, check its settings or dial *#06#. If it doesn’t appear, please check your official device specifications or look in the settings menu, as some compatible devices may not show the EID immediately.

Can I use an eSIM and a physical SIM card at the same time?

It depends on the device. Some devices support dual SIM functionality, allowing for the use of both an eSIM and a physical SIM card at the same time. Others may only support one SIM card at a time.

Can I use the same eSIM across multiple devices?

Unfortunately, you cannot. An eSIM can only be used on one device at a time. If you switch devices, you will need to purchase a new eSIM.

Does eSIM require an Internet connection for installation?

Yes, it does. An internet connection is required to download and activate the eSIM profile on your device.
We recommend using a stable Wi-Fi connection whenever possible. If you're arriving in Japan, you can use the free Wi-Fi available at airports like Haneda, Narita, or Kansai to activate your eSIM. Alternatively, you can install the eSIM profile just before your flight to Japan to ensure a smooth transition and instant connectivity upon arrival.

How can I install eSIM?

We provide two ways to install and activate your eSIM:

1. QR code scan
2. Manual activation using an activation code
We recommend the method based on your device's operating system:

  • iOS users:Use the QR code. It will be displayed on the app screen immediately after purchase, along with clear step-by-step instructions. Simply tap the INSTALL button to start installation on your current device, or scan the code if you're installing it on another device.
  • Android users:We recommend the manual activation method. Just copy the activation code provided in the app and paste it into your phone’s eSIM settings.

For detailed guidance, check out our “How to Set Up an eSIM” page!

Why won't my eSIM work?

If your eSIM isn’t working, please check the following:

  1. Is your phone unlocked? If you bought your phone from a mobile carrier, it might be SIM-locked. Contact your carrier to confirm whether your device is unlocked and can use third-party eSIMs like ours.
  2. Have you already activated the eSIM once? An eSIM can typically only be installed once. If you've already activated it on another device or deleted it, it may no longer be usable.
  3. Check your mobile settings:
    - Wi-Fi: OFF
    - Airplane Mode: OFF
    - Data Roaming: OFF
    - Mobile Data: ON
  4. Check your APN settings (for Android users): Make sure the Access Point Name (APN) is set correctly according to our setup guide. Incorrect APN settings can prevent mobile data from working. APN settings are usually configured automatically for iOS. However, if you want to use tethering or share your data (Personal Hotspot), you may need to enter the APN manually.
  5. Restart your phone: After installation and setup, restarting your device can help your phone register the new network properly.
  6. Check your signal bar/network name: If there’s no signal or network name "IIJ", the SIM may not be activated properly, or you may be in an area with poor coverage.
  7. Check for software updates: Make sure your device has the latest system updates installed, as these sometimes affect eSIM compatibility.
  8. Make sure your phone has enough battery power. Low battery levels can sometimes affect performance, especially during installation or network connection.

Does eSIM drain my phone battery?

Not significantly. An eSIM does not use more battery than a traditional physical SIM. However, depending on how it's used, a few factors can influence power consumption:

  1. Dual SIM usage(for example, when you use eSIM for data and physical SIM for voice): Your phone must maintain two network connections simultaneously, which increases battery usage.
  2. Roaming:Some eSIMs from global plans continuously search for the best network, which can lead to higher power consumption. → Not applicable to TOP SIM because it does not require roaming.
  3. Poor signal strength:Whether using a physical SIM or eSIM, being in areas with weak coverage (like underground or remote locations) makes your device work harder to stay connected, using more battery.
  4. Frequent network switching:eSIMs that jump between networks (common with some travel SIMs) can consume more power. → Not the case with TOP SIM, which always connects to the IIJ network, ensuring stable connectivity.

Can I reinstall the profile after I deleted it or the app?

If you deleted the eSIM profile, it cannot be reinstalled. You will need to purchase a new plan and install a new eSIM profile.
If you only uninstalled the TOP SIM app, but the eSIM profile is still on your device, you can continue using the remaining data. There’s no need to reinstall the profile. However, without the app, you won’t be able to recharge your plan. To recharge, you will need to reinstall the app.

Usage & Features

Can I use WhatsApp or other messaging apps with the eSIM in Japan?

Yes, you can!
TOP SIM is a data-only eSIM, which means you can use WhatsApp, LINE, Messenger, and other internet-based communication apps to send messages, make voice and video calls, and stay connected while in Japan.

Important: Please ensure your app accounts are already set up before you arrive, especially if they require verification using your home country phone number.

Can I send an SMS or make a call with TOP SIM?

No, TOP SIM is a data-only SIM. It does not support SMS or voice services. To make and receive calls, you may subscribe to our My 050 Number service.
Or, you can use internet connection-based calls and messages (e.g., WhatsApp, Messenger, Instagram, LINE, etc.)

Does an eSIM change my phone number?

No, it doesn't.
Our TOP SIM eSIMs do not come with a phone number. They are data-only, which means you can use internet-based apps like WhatsApp, LINE, and Messenger for messaging and calls, but you won’t be able to make or receive traditional voice calls or SMS. Your existing phone number (from your physical SIM or another eSIM) will remain unchanged.

Can I use your eSIM in another country while roaming?

No, TOP SIM is only available for internet connection in Japan.

If I run out of data, what will happen?

If you consume all the data, your speed decreases to 200 kbps. Please choose a new plan of your preference and recharge to regain a speedy connection.

Can my eSIM be extended?

Yes, each recharge within the eSIM's validity period can extend it. Any unused data from the previous period can be rolled over to the new period, but only for a maximum of 180 days.

Purchase, Account & Recharge

Can I order your eSIM before arriving in Japan?

Yes, you can order your TOP SIM eSIM before arriving in Japan.
You may also install the eSIM profile while still in your home country. However, please note that you won’t be able to test the internet connection until you arrive in Japan. The eSIM will only connect to the local network and become activated once you're in Japan, provided it's properly configured.

Important:The eSIM's validity period starts 45 days after purchase, even if you haven’t installed or used the profile yet. So please make sure to time your purchase accordingly.

Do I need to create an account?

No, you do not!
Our service is designed to be as user-friendly and hassle-free as possible. That means:

  • No account registration required!
  • No login or passwords to remember!
  • No eKYC (identity verification) needed!

However, we strongly recommend that you do not uninstall the app after installing your eSIM. If you uninstall it:

  • You won’t be able to recharge your eSIM plan.
  • You’ll lose the benefit of paying less by continuing with the same eSIM.
    Keep the app installed to enjoy seamless recharges and better value!

How can I recharge my eSIM?

It’s very simple!
Just open the TOP SIM app, choose your preferred data plan, and follow the on-screen instructions to complete your recharge.
Currently, we accept cash payments at convenience stores in Japan. But good news — we’re working on adding credit card and other digital payment options very soon!

Can I recharge after the eSIM expires?

It is possible to recharge the eSIM only within 7 days after the plan expiration date, but you need to connect to Wi-Fi first.

Can I cancel my order?

Unfortunately, once the payment is completed, cancellations and refunds are not possible.
However, if you selected the "My Payment" (cash at convenience store) option and have not yet made the payment, you can simply choose not to complete the transaction — no further action is needed if you’ve changed your mind.

What is an SM-DP+ address?

An SM-DP+ address works like an activation code. It's a special Internet link provided by your mobile carrier to activate your phone’s eSIM, which is a digital SIM card built directly into your device. When activating your eSIM, you’ll enter or scan this link, allowing your phone to securely download all necessary network settings and connect to your carrier without needing a physical SIM card.

Physical SIM Card

Why there is no Internet?

Please check the following:

  1. Verify the APN settings (a network path for all cellular data connectivity) according to this manual: [iOS], [Android].
  2. Ensure that your mobile data is ON, airplane mode is OFF, and Wi-Fi is OFF.
  3. Reboot the device until you see the IIJ antenna pictogram.
  4. Devices with SIM lock or network usage restrictions imposed by other carriers may not be compatible. In such cases, you may need to request unlocking from the purchase source or carrier.
  5. For dual SIM devices, please check if you are using the correct SIM slot. Try switching and performing the APN settings for the other slot as well. Do not forget to reboot the device.
  6. Ensure that the preferred network type is set to anything other than “GSM only”

Why is my data speed slow?

Most likely, you have consumed your data allowance, causing your speed to decrease to 200 kbps. Please choose a new plan of your preference and recharge to regain a speedy connection.

If this is not the case, please check the following:

  1. Ensure that your APN settings are correctly configured according to this manual: [iOS], [Android].
  2. Verify that your mobile data is ON, airplane mode is OFF, and Wi-Fi is OFF.
  3. Reboot your device.
  4. Check if there are any network outages or maintenance activities in your area.

If the issue persists, please contact our customer service for further assistance.

Can I use tethering with this SIM?

Yes, we do not restrict data for tethering, but please check that your device allows tethering.

For iOS, you need to add the APN settings to the Personal Hotspot field.

How can I check my data daily usage?

Please refer to the Mobile Data Usage settings on your device.

Why can't I activate my SIM by scanning a barcode or entering it manually?

This is likely due to no internet connection. Please check your APN settings, ensure mobile data is ON, and make sure Wi-Fi and airplane modes are OFF.

Why is my initial 5GB valid for more than 30 days?

The initial 5GB of data is valid for a full 60 days if the APN settings and SIM activation are completed on the same day. Please note, if the APN settings and activation are done on different days, the validity period will be shorter.

Why does my device not recognize the SIM?

Your SIM may be defective. Please contact our customer service for support.

Can I use the same SIM card with different devices?

Yes, as long as the device you use is compatible with TOP SIM, you can interchange your devices using the same SIM.

Please do not forget to set up the APN and reboot the new device. For activation, you will need to either scan the barcode from the cardholder or, if you do not have it anymore, use the manual SIM ID (ICCID) input link instead. The SIM ID number is printed on your SIM card and starts with 898103.

Can I use TOP SIM in another country while roaming?

No, TOP SIM is only available for internet connection in Japan.

Is there a PIN code?

Yes, the PIN code is "0000". Usually, it is not required. However, entering the wrong PIN code multiple times will result in blocking your SIM. In that case, a PUK code will be necessary. Please contact our customer service for support.

I lost my SIM. Is it possible to reissue it?

No, it is not possible. Please purchase a new SIM from our store: https://shop.brastel.com/

Why can't I pay with the barcode at a convenience store?

Please check the following:

  1. Every Tuesday from 22:00 to 9:00, there is network maintenance during which it is not possible to download the barcode. Please perform the purchase at another time.
  2. The barcode scanner in the store may not read the barcode properly if the screen has scratches or a protective film. 
  3. The barcode expires at midnight. Please download a new barcode from the TOP SIM app.
  4. Barcodes may not be displayed on some smartphone models, such as iPads and tablets. The following smartphone device environment is recommended for usage:
  • OS: iOS 10.0 or later, Android 5.0 or later
  • Browser: The latest version of Safari or Google Chrome
  • Screen size: 4.0 inches to 6.7 inches

Why doesn’t my activity page show the additional data I recharged?

If you don't see the updated data balance in the app, try the following steps:

  • Refresh the screen – swipe down on the screen and release to reload the latest information.
  • Close and reopen the app – the data might not have been refreshed yet.
  • Check your internet connection – a weak or unstable signal may prevent data from updating.
  • Clear the app cache – you can do this in your phone settings if the issue persists.
  • Restart your phone – sometimes, this helps refresh system data.

If the data balance still doesn’t appear after these steps, please contact support via the chat icon in the top right corner.

Can I recharge after the SIM expires?

It is possible to recharge the SIM only within 7 days after the expiration date, but you need to connect to Wi-Fi first.

Can my SIM be extended?

Yes, each recharge within the SIM's validity period can extend it. Any unused data from the previous period can be rolled over to the new period, but only for a maximum of 180 days.

My SIM has expired. Where can I purchase a new SIM?

You can order a new SIM from our Shopify page: shop.brastel.com. Simply add the desired quantity to your basket and proceed to checkout.

If you are purchasing more than 10 SIMs, please explore our reseller discount option: https://shop.brastel.com/pages/top-sim-reseller-program

Can I send an SMS or make a call with TOP SIM?

No, TOP SIM is a data-only SIM. It does not support SMS or voice services. To make and receive calls, you may subscribe to our My 050 Number service.

Do I need to cancel or return the TOP SIM when I return home?

There is no cancellation procedure. If you don’t recharge your TOP SIM and it expires, the service will automatically end. You do not need to return the SIM.