Updated: 2025-04-28 11:15:00
First time hearing about "eSIM" and not quite sure what it is? Planning a trip to Japan but getting overwhelmed by terms like roaming, SIM cards, or mobile data? Don’t worry — this article is made for you. We’ve rounded up 10 of the most common questions people have when using a Japan eSIM for the first time, and we’ll explain everything in plain English. From speed and compatibility with LINE, to installation tips and hotspot sharing, we’ve got it all covered. By the end of this guide, even if you’re not tech-savvy, you’ll feel confident choosing the right eSIM for your trip.
Definitely — as long as you’re using a local eSIM that connects directly to Japanese networks like docomo or SoftBank. These are the same networks that locals in Japan use every day, so you’ll have no problem with speed for Google Maps, Instagram, YouTube, or even Zoom meetings.
If you’ve heard complaints about "slow eSIM" service, it’s usually from people who bought a global or roaming-based eSIM that routes data through another country. To avoid that, make sure you pick a Japan-specific eSIM. CDJapan Rental’s eSIMs, for example, run on docomo’s network for maximum speed and coverage.
Absolutely. If you're keeping your regular phone number (like your U.S. SIM) active, LINE will continue to work just like before. Even if you remove your regular SIM, as long as you don't log out of LINE or uninstall the app, you won't lose your account or contacts.
Many travelers to Japan rely on LINE for hotel communication, restaurant reservations, and chatting with local friends — and it works just fine over an eSIM.
Yes — at least with Japan eSIMs like the one from CDJapan Rental, hotspot sharing is supported. That means you can share your data with a friend’s phone, your laptop, or a tablet.
Some eSIMs (especially from certain global providers) may block hotspot use, but local eSIMs rarely do. Just be sure to set up the APN correctly if you're using iPhone — that’s what controls whether the hotspot toggle appears. CDJapan Rental provides step-by-step instructions if you need them.
For more information, please read the following passage: Can I Use My Japan eSIM as a Hotspot for Friends?
It depends what kind of calls you mean. eSIM data plans usually don’t come with a Japanese phone number, so you can’t make traditional phone calls. But you can absolutely use internet-based calling apps like LINE, WhatsApp, Messenger, or FaceTime Audio.
If you need to make local calls to restaurants, hotels, or Japanese phone numbers, using LINE is usually enough — many places are used to messaging. For business travelers who require voice calls, a rental SIM with a Japanese number might be a better option.
If you’re using a Japan-only eSIM from a reputable provider, the price you see is usually the final price. There’s no daily surcharge or roaming fee like what you'd get from Verizon or AT&T.
That said, be careful when buying from lesser-known eSIM marketplaces. Some plans come with vague data limits or throttle speeds after a certain amount of use. Always read the fine print — or better yet, choose a provider with transparent, fixed data packages.
Unfortunately, most eSIMs — including the ones from CDJapan Rental — cannot be reinstalled once deleted. If you accidentally remove the eSIM from your device, you will need to purchase a new one.
So be extra careful: after you install the eSIM, avoid deleting it or tapping "Remove Cellular Plan." If your phone suddenly malfunctions, contact customer support right away. We’ll check if there's any way to issue a replacement.
Keep in mind that each eSIM is tied to your device, and you can’t install it on multiple devices at once. If you switch phones during your trip, be sure to contact your provider first to ask about transfer options.
Most eSIMs come with a QR code and simple instructions. You scan the code under Settings → Cellular → Add eSIM (on iPhone), and the profile gets installed in seconds. After that, turn off your main SIM, make sure roaming is off (if required), and you're good to go.
Some eSIMs activate automatically when installed, while others start counting from the moment you first connect to data in Japan. Always check the activation rules before your flight so you can plan accordingly.
Yes, if your phone supports dual SIM. For example, you can keep your U.S. SIM for calls and texts, and use the Japan eSIM for data. Just make sure to set your Japan eSIM as the default for cellular data in your phone settings.
That said, if your home carrier charges for roaming — even just keeping the SIM active — you might want to disable it entirely or use airplane mode to avoid surprise charges.
If you realize you picked a plan with too little data, don’t panic — you can always purchase another eSIM if needed. Many travelers find it easier to start with a moderate plan to avoid running out too soon.
If you bought a plan that’s too big, well — better to have extra than to run out halfway through a day trip in Kyoto. Planning ahead based on your trip length and expected usage is the safest bet.
You’ll need an eSIM-compatible and unlocked phone. Most iPhones from the XR onward support eSIM, as well as many Android models from Google, Samsung, and others. If you're using an iPhone 15 from the U.S., you might not even have a physical SIM tray — so eSIM is your only option.
If you're not sure whether your phone works, check your device settings or contact your provider. CDJapan Rental also has a compatibility list if you need help.
If you’re still feeling unsure about which Japan eSIM to pick, you’re not alone — especially if it’s your first time using one. The good news? Once you’ve tried eSIM, many travelers say they’d never go back to physical SIM cards or expensive roaming.
CDJapan Rental offers local Japan eSIMs with clear pricing, no hidden fees, and English support. Whether you're heading to Tokyo for work or exploring Kyoto on vacation, you can get connected the moment you land — no pickup or shipping required.
Want to see available plans? Check out CDJapan Rental’s Japan eSIM options.
