Buy a 20 GB plan
Saily sells 20 GB for Japan at $24.99.
Prices checked 11 Oct 2026. Affiliate links: we may earn a commission at no cost to you. Compare all providers in our Japan eSIM guide.
How much eSIM data do you need for Japan?
Set how long you’re staying and what you’ll do on mobile data each day. The calculator tells you how many GB to buy and whether an unlimited plan makes more sense. It takes a minute and saves buying twice.
Hours a day away from Wi-Fi
Count only what you do on mobile data. Anything on hotel or café Wi-Fi is free.
You need about
12 GB
for 10 days, about 1.2 GB a day, including 15% for background use.
Most of it is short videos and social media (7 GB).
What uses data, and how much
Video is what empties a plan. Everything else a visitor does on the move (maps, train times, messages, translation) is light. The calculator uses these rates per hour of use:
| Activity | GB an hour | Source |
|---|---|---|
| Maps, messages and browsing | 0.05 | Our estimate |
| Short videos and social media | 0.7 | Our estimate |
| Streaming video | 0.7 | Netflix: standard quality, up to 0.7 GB an hour |
| Video calls | 1.08 | Zoom: 1.2 Mbps up and down for a 720p call, about 1.08 GB an hour |
| Music and podcasts | 0.072 | Spotify: high quality is about 160 kbit/s, 0.072 GB an hour |
| Laptop on your phone’s hotspot | 0.3 | Our estimate |
We add 15% on top for things you don’t see: apps refreshing, map tiles loading, photos syncing. Turn off cloud photo backup over mobile data before you fly; it is the most common reason a plan runs out early.
The rates marked “our estimate” have no official figure behind them. We are measuring them on real Japanese networks and will replace them with our own numbers when the tests are done.
Saving data in Japan
- Download offline Google Maps for each city before you leave home.
- Download shows and playlists on hotel Wi-Fi instead of streaming them on the train.
- Set Instagram and TikTok to their data-saver mode. Both have one, and it lowers video quality on mobile data.
- Free Wi-Fi is common in stations, convenience stores and hotels, but it is patchy on trains and outdoors. Don’t plan around it for navigation.
Choosing a provider? See our best eSIM for Japan guide, and how to set up an eSIM before you fly.
FAQ
How much data do I need for 10 days in Japan?
For a visitor who uses maps and messaging for six hours a day and scrolls social media for an hour, 10 days comes to about 12 GB, so a 10 GB plan is tight and 20 GB is comfortable. Streaming video or making video calls away from Wi-Fi adds about 0.7–1 GB for every hour, so heavy users should buy an unlimited plan.
Does Google Maps use a lot of data?
Not much. Directions, train times and messaging are light compared with video: we budget 0.05 GB an hour of active use. You can cut it further by downloading offline maps for the cities you visit before you fly.
What uses the most data on a trip?
Video. Netflix says standard-quality streaming uses up to 0.7 GB an hour and HD up to 3 GB. Instagram Reels and TikTok also play video as you scroll, so an hour of social media can cost as much as an hour of streaming.
Is unlimited data worth it in Japan?
If you expect to use 2 GB a day or more, yes: at that rate you are near or past the biggest fixed plans. Unlimited plans also suit anyone sharing a hotspot with a laptop or travel companion.
Rates checked 16 Oct 2026.