eSIM for Japan
For two weeks in Japan, 4,90 € with 3 GB covers most people: Maps at all hours, WhatsApp and the translator. If you'll be on the phone all day or sharing data, the 1 GB-a-day pass comes to 20,90 €. It runs on NTT docomo, Rakuten Mobile, KDDI/au and SoftBank, and you install it at home on Wi-Fi before you fly.
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You arrive at Shinjuku at seven in the evening. It's the busiest station in the world, it has two hundred exits and not one of them is named anything like the one you're after. Your hotel is four hundred metres away in a straight line, and there is no earthly way of knowing in which direction. That's when — exactly then — you find out whether you have data.
How many GB you really need
You get around Japan phone in hand more than almost anywhere else: Maps for the metro, the translator for menus, the train planner. Even so, maps use little data. A whole day of navigating comes to about 100 MB, and translating a menu with the camera to far less than you'd expect.
What sends the total soaring is video. If you keep Instagram and video calls for the hotel, two weeks fits comfortably into 3 GB.
| Plan | Price | Who it's for |
|---|---|---|
| 7 days · 1 GB | 2,90 € | A long layover, or a week with hotel Wi-Fi |
| 15 days · 3 GB | 4,90 € | The typical trip: Tokyo, Kyoto, Osaka |
| 30 days · 5 GB | 5,90 € | Three weeks, or a month of moderate use |
| 30 days · 10 GB | 9,90 € | Two people sharing, or heavy use |
| 30 days · 20 GB | 14,90 € | Working from there |
A plan's days are a maximum, not an obligation. For a ten-day trip, 30 days with 5 GB at 5,90 € costs one euro more than 15 days with 3 GB and gives you nearly twice the data. Compare before assuming the short plan is the cheap one.
Which networks it uses
NTT docomo, Rakuten Mobile, KDDI/au and SoftBank. They're the country's four operators, so the coverage is the whole country's: 4G and 5G in the cities, on the Shinkansen and in the villages. Japan has one of the densest mobile networks in the world, and that doesn't depend on the card you're carrying: the network is the same for everyone.
Where the signal does drop is in the long mountain tunnels and the odd rural valley up north. That happens to every SIM, Japanese ones included.
Why it matters more in Japan than elsewhere
Two things you don't expect. First: Japanese public Wi-Fi is patchy. There's some in Starbucks, in the convenience-store chains and in many stations, but it usually asks you to register with an email, drops the moment you leave the platform and doesn't cover the street, which is where you actually need Maps.
Second: as a tourist you can't buy a Japanese prepaid SIM with a phone number. The law requires residency. What is sold to foreigners are data-only cards, which is exactly what an eSIM does — minus the queue and the photocopied passport.
Install it before you fly
- Buy it and get the QR by email, instantly.
- Install it at home, on Wi-Fi. Installing needs a connection; activating doesn't.
- When you land at Narita or Haneda, switch on the data line and turn off roaming on your Spanish SIM.
- The days start counting when the eSIM first connects to a Japanese network, not when you buy it.
Leaving it for the airport is the classic mistake. Installing needs internet, and Narita passport control with three flights landing at once is not where you want to discover that the Wi-Fi asks for a verification code by SMS.
Does the eSIM give me a Japanese number?
No. The plans are data only: no Japanese number, no SMS. Your Spanish number stays active for calls and WhatsApp, because the eSIM goes in as a second line and your usual SIM stays where it is.
Can I share data with another phone?
Yes. The Japan plans allow hotspot sharing, so you can be the access point for your travel companion's phone or laptop. Bear in mind you'll be spending from the same gigabytes.
Does it work on the Shinkansen?
Yes, with coverage for almost the whole ride. The long tunnels between mountains cut the signal for a few seconds, same as with any Japanese card.
When do the days start counting?
From the first connection to a Japanese network, not from purchase. You can buy it weeks ahead and install it calmly at home without using up a single day.
What if my phone doesn't support eSIM?
Almost every mid-range and high-end phone from recent years does, but check before you buy: in Settings you can see whether your model takes eSIM. If it doesn't, no eSIM will work on it, whoever sells it.
Something off, or a price changed? Write to ayuda@zasesim.com and we'll fix it. Data when you land.