Technical Specifications
Seamless signal on Bullet Trains & rural areas.
Apple
Android
You can buy your Japan eSIM online from ByteSIM in just a few clicks — or directly through our iOS and Android apps. After purchase, your eSIM QR code will be instantly delivered to your email and available in the app.
📲 For iOS 17 and later, you can install your eSIM with just one tap inside the ByteSIM iOS App — no QR code needed.
📱 On Android, simply follow the on-screen instructions to add the eSIM manually or via QR scan.
🚀 Activation starts only when you arrive in Japan and turn on data roaming — no early billing, no physical SIM card, and no ID needed.
✅ Works on eSIM-compatible devices including iPhones, Android phones, and tablets.
ByteSIM’s Japan eSIM connects to SoftBank and KDDI (au) — two of the country’s top mobile networks.
📶 According to Opensignal April 2025, KDDI leads in overall 5G experience, while SoftBank offers the widest 5G availability across Japan.
💡 Your eSIM automatically switches between networks for the strongest 4G/5G signal wherever you go — ideal for travelers moving across cities like Tokyo, Osaka, Kyoto, and beyond.
Yes, you can. ByteSIM eSIM fully supports hotspot and tethering, with no speed limits — even on unlimited plans.
🔥 Share internet via 2.4GHz (for wider compatibility) or 5GHz (for faster speeds), depending on your device — ideal for laptops, tablets, and travel companions.
No, ByteSIM Japan eSIM does not support phone numbers, voice calls, or SMS, due to local telecom regulations.
The timing for installing an eSIM for Japan can depend on your specific travel plans and preferences. It's a good practice to install your eSIM on the day of your travel to Japan, especially if you want to ensure seamless connectivity as soon as you arrive.
ByteSIM Japan eSIM plans follow two service timing models, depending on the plan type and carrier:
Daily SoftBank Plans
For plans that reset daily (e.g. 500MB/day), the data resets each day at 23:00 Japan Time (UTC+9), regardless of the activation time.
Total Data & Unlimited Plans (KDDI + SoftBank dual-network)
These plans follow a 24-hour cycle starting from the moment of activation. For example, if activated at 10:00 AM local time, it will expire at 10:00 AM the next day.
Currently, top-up and extension are not supported due to the anonymous nature of our eSIM products.
💡 But the good news: you can simply buy a new plan at any time — often with a better deal thanks to our reward points and member discounts. The experience is just as seamless, and often even cheaper.