FAQ
- General FAQ
- Device Compatibility FAQ
- Setup & Usage FAQ
- Network Quality & Coverage FAQ
- Wi-Fi Spot Usage FAQ
- Purchase, Validity & Reissue FAQ
General FAQ
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Q.What is JAPAN PREMIUM SIM?
A.It is a data-only SIM brand for use exclusively within Japan. This website offers eSIMs that can be used immediately after purchase. The service provides unlimited internet access for visitors to Japan using a high-quality local network (au).
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Q.Can I use it outside of Japan?
A.No, it is for use within Japan only. It cannot be used abroad.
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Q.Which carrier’s network does it use?
A.It uses KDDI (au), one of the world’s highest quality MNO networks.
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Q. What’s the difference between JAPAN PREMIUM SIM and regular roaming eSIMs?
A.Because it uses a local network, it offers higher communication quality and more stable connectivity.
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Q.Can I use voice calls or SMS?
A.This is a data-only SIM. Voice calls and SMS are not supported.
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Q.Can I use tethering?
A.Yes, tethering is available. As a guideline, the following data volumes are estimated:
4 days: 3GB
7 days: 6GB
10 days: 9GB
15 days: 15GB
31 days: 30GB -
Q.Are there any data limits?
A.All plans offer unlimited data. There are no speed restrictions or daily usage limits, unlike many other services.
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Q.What plan options are available?
A.You can choose from 5 plan durations: 4 days, 7 days, 10 days, 15 days, and 31 days.
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Q.Can I pay in currencies other than Japanese yen?
A.Purchases must be made in Japanese yen, but you can pay with your credit card as usual.
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Q.I accidentally purchased the wrong plan. Can I cancel it?
A.Unfortunately, cancellations are not possible because eSIMs are issued immediately upon purchase.
Device Compatibility FAQ
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Q.Which devices are compatible?
A.Any smartphone, tablet, or mobile router that supports eSIM can be used.
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Q.Are major devices like iPhones and Pixels supported?
A.Yes, many of the latest models are supported, but please confirm your device supports eSIM before purchasing.
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Q.Can I use it on Android devices?
A.Yes. Depending on the Android model, you may need to configure eSIM and APN settings manually.
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Q.Can I use it on a device that is SIM-locked?
A.Only SIM-free or carrier-unlocked devices are supported.
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Q.Do you offer physical SIM cards?
A.No. Only eSIMs are available for purchase on this website.
Setup & Usage FAQ
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Q.Can I use it immediately upon arriving in Japan?
A.Yes. If you set up the eSIM in advance, you can start using it right after you arrive in Japan.
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Q.I’ve never used an eSIM. Is setup easy?
A.Yes. After purchase, simply scan the QR code sent to you to complete the setup easily.
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Q.When does the eSIM become active?
A.Your usage starts the day the eSIM first connects to a network in Japan. That day counts as Day 1.
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Q.Do I need Wi-Fi to set up the eSIM?
A.Yes, an internet connection is required during setup. Please configure it in a Wi-Fi environment.
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Q.For iOS, do I need to install an additional profile?
A.No. You can use it immediately after scanning the QR code.
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Q.What should I do if an error occurs during setup?
A.Try restarting your device. Please do not delete the eSIM, as it cannot be reinstalled.
Network Quality & Coverage FAQ
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Q.Is 5G supported?
A.Yes, both 5G and 4G LTE are supported.
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Q.What are the supported bands?
A.5G: n28, n3, n41, n77, n78, n257
4G: Band 1, 3, 11, 18/26, 28, 41, 42 -
Q.How wide is the coverage area?
A.The coverage area is among the best in Japan. 4G covers 99.9% of the population, and 5G covers over 90%.
au coverage map -
Q.Does it work in subways or mountainous areas?
A.It works in most places. However, availability may vary depending on building structure and location. Please refer to the au coverage map for details.
Wi-Fi Spot Usage FAQ
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Q.Can I use Wi-Fi spots for free?
A.Yes, if you see au/Wi2 Wi-Fi spots, you can also use them for free.
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Q.Where can I find available Wi-Fi spot locations?
A.You can check them here.
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Q.Is the connection secure?
A.Yes. Unlike public/free Wi-Fi, the connection is encrypted and secure.
Purchase, Validity & Reissue FAQ
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Q.When does the usage period begin?
A.The period begins from the day you connect to the local (au) network.
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Q.What happens after the plan period ends?
A.The connection will stop, and it cannot be resumed. Please purchase a new plan if you want to continue enjoying the service.
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Q.What if I accidentally delete the eSIM?
A.Reissue is generally not possible. Please be careful not to delete it.
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Q.Can I extend the plan if I stay longer in Japan?
A.It's not possible to extend, but you can purchase a new eSIM plan and use it immediately.