For maps, messaging, translation apps and some social media, about 0.5 to 1GB a day is enough. If you stream video, take video calls or share your connection with a laptop, plan for 2GB a day or more, or get an unlimited plan.
Rough guide by trip
| Trip | Light use (0.5GB/day) | Moderate use (1GB/day) | Heavy use (2GB+/day) |
|---|---|---|---|
| 5 days | 3GB | 5GB | 10GB or unlimited |
| 1 week | 5GB | 10GB | 15GB or unlimited |
| 2 weeks | 10GB | 15–20GB | Unlimited |
| 3 weeks | 10–15GB | 20GB+ | Unlimited |
Not sure where you fit? Your phone tracks it: look at mobile data used in a typical week at home, divide by seven, and add a margin, since you’ll lean on maps more while travelling.
What uses data on a trip
| Activity | Rough data use |
|---|---|
| Messaging (text, photos) | Very little, apart from sending videos |
| Google Maps or Apple Maps navigation | Small, especially if you download offline maps first |
| Translation apps (text and camera) | Small |
| Social media scrolling with video | Roughly 0.5–1GB an hour |
| Video calls | Roughly 0.5–1.5GB an hour |
| Streaming video | About 1GB an hour in standard definition, up to 3GB an hour in HD (Netflix’s figures) |
| Uploading videos | Large. Wait for hotel WiFi if you can |
These are rough figures from typical app settings, apart from the streaming figure, which is Netflix’s own. Actual use varies a lot with video quality.
Is free WiFi enough?
Japan has free WiFi in airports, many train stations, convenience stores and cafes, and most hotels have it in rooms. It’s useful for big downloads, but it’s patchy on the street and often needs a sign-up per network, so it’s no substitute for mobile data when you’re navigating.
When unlimited makes sense
Unlimited plans cost more per day, but they’re worth it if you:
- stream video or take regular video calls
- share your connection with a laptop or other phones
- would rather not think about data at all
Read the small print first. Some “unlimited” plans slow you down after a daily allowance, and some don’t allow hotspot use. The comparison table shows which allow hotspot use.
Ways to use less
- Download offline maps for the cities you’re visiting before you fly.
- Set apps to back up photos only on WiFi.
- Lower video quality in streaming apps.
- Download shows and playlists on hotel WiFi.
Questions people ask
Is 20GB enough for 2 weeks in Japan?
For most people, yes. It’s about 1.4GB a day, which covers maps, messaging and a fair amount of social media. Heavy video users may want unlimited.
Is 10GB enough for 2 weeks?
For light use, yes: about 0.7GB a day. If you post a lot of video or stream, it will be tight.
How many GB should I buy for Japan?
Multiply your days by 0.5GB (light), 1GB (moderate) or 2GB (heavy), then round up to the next plan size. The cost calculator does this for you.
How fast is mobile internet in Japan?
Fast in cities on all three major networks, with 5G widely available in urban areas. Speeds drop in tunnels, on some rural lines and in the mountains. See how we test speed.
Written by Stephen
Stephen lives in Osaka. fly-jpn is where he compares eSIMs, SIM cards and pocket WiFi for visitors, using what he has learned as a resident. A plan is only described as tested when he has bought it and used it in Japan himself.