Choosing the right Japan eSIM size
Japan burns more data than travellers expect, because maps and train apps stay open all day. This is how many gigabytes each trip length really takes.
Quick answer
- A typical Japan trip uses roughly 800MB–1.5GB a day, so five to seven days lands on 5GB, and ten days or more is more comfortable at 10GB.
- If you tether for travel companions, multiply by the number of devices leaning on your line rather than adding a small buffer.
- Check the validity as well as the gigabytes: the clock starts at first activation, not at purchase.
Start from the number of days, not the number of gigabytes
Most people pick the plan that looks like the best value and then hope it holds. The harder-to-miss method is to start from the days you will actually be there, multiply by what your trip style consumes per day, and round up. Leftover data costs you nothing; running dry in the middle of Shinjuku costs you the afternoon.
| Trip length | Maps, chat, photos | Video shot and uploaded nightly | Tethering one extra device |
|---|---|---|---|
| 3 days | 3GB | 5GB | 5GB |
| 5 days | 5GB | 10GB | 10GB |
| 7 days | 5GB | 10GB | 10GB |
| 10 days | 10GB | 20GB | 20GB |
| 14 days | 10GB | 20GB | 20GB |
These are our planning estimates from typical usage, not measurements from your own phone.
Why Japan eats more data than most destinations
- Transfers in Tokyo and Osaka mean opening an app for the platform and the minute almost every time you change line
- Signs and menus are largely in Japanese, so camera translation gets used far more than people expect
- Many restaurants take bookings only in an app, and those bookings happen during the day
- Visit Japan Web and train QR codes get opened at the gate — the exact moment you cannot be offline
Who the per-day plans suit
Alongside the single-bucket plans, Japan also has per-day plans that refill every day. They suit people whose usage is heavy and even — working while travelling, filming every day. If your trip alternates hotel days with all-day walking days, a single bucket usually wins, because an unused daily allowance disappears at midnight.
Validity, not gigabytes, is where people actually get caught
Our Japan shelf carries 7-, 15- and 30-day validities. Buying 5GB with 30 days for a six-day trip simply leaves data behind; buying 3GB with 15 days for a 16-day trip expires the day before you fly home. Read both numbers together, and leave at least one day of headroom for a delayed flight.
If the maths still leaves you unsure
- 1Look at last month's actual usageOpen your phone's mobile data settings and read the last billing cycle, then divide by 30. Your own daily average beats anybody's general estimate.
- 2Add the travel premiumOn the road you lean on maps and translation far more than at home, so add roughly half again to your own average.
- 3Round up to the nearest planIf the maths says 7GB, take the 10GB rather than the 5GB: topping up mid-trip usually costs more than buying the headroom up front.
FAQ
Is 1GB enough for a three-day trip?+
Only if you live on hotel Wi-Fi and switch mobile data on just to find your way. With maps open all day, 1GB usually goes within the first day or two.
Which network does a Japan eSIM use?+
It depends on the plan. Each plan page lists the networks the supplier publishes for it — read that before buying, because we would rather show the supplier's own statement than generalise over it.
If the data runs out before I fly home, do I need a whole new eSIM?+
Not always — most Japan plans can be topped up on the profile you already installed. Message us at any hour and we will say whether yours can be topped up or whether a fresh plan is cheaper.
I am visiting several countries — Japan plan or Asia plan?+
If more than half the trip is in Japan, a Japan plan plus a small plan for the other country usually wins. If the days are split evenly, one Asia plan covering both is simpler because you never switch profiles.
Instagram and TikTok have no web share button, so we open your phone's share sheet or copy the link instead.