eSIM for Japan: internet from the moment you land

An eSIM (from embedded SIM) is a digital SIM card built into the phone itself. Instead of inserting a piece of plastic into the tray, you download an operator profile onto the phone and you are done. For a trip to Japan that means you can buy your data online from home, install it before leaving and not have to look for or change any card on arrival.

Compared with the traditional physical SIM, the eSIM has three clear advantages for the traveller: there is nothing to pick up at the airport or have sent by post, you do not have to remove or store your home SIM (it stays inside the phone, on another "line"), and you activate it yourself in a couple of minutes. The physical SIM still makes sense mainly if your phone does not support eSIM.

And compared with pocket WiFi — that portable router you rent — the eSIM is not one more device to carry, charge every night and return at the end of the trip: it is inside your phone. Below we compare the four options in detail.

To use an eSIM in Japan your phone must meet two conditions:

• Be eSIM-compatible. Most mid-to-high-range phones of recent years are. As a guide: iPhones from the iPhone XR/XS (2018), Samsung Galaxy from the S20 series onwards and Google Pixel from the Pixel 4 support eSIM. Rather than relying on a list (the models change every year), the most reliable thing is to search for your exact model + "eSIM" or check in your phone settings whether the option to "Add eSIM" or "Add data plan" appears. Watch one detail: some phones bought in certain countries (for example iPhones from mainland China or some Samsung from the US) come with the eSIM disabled from the factory, so check your specific one.
• Be unlocked. The phone must not be tied to a specific carrier. Almost all phones bought unlocked are; if you bought it on a contract or tied to a company, it is worth confirming it accepts SIM/eSIM from other operators before travelling.

The process is simple and, except for the last step, it is best done before leaving home, with WiFi and at your ease:

1. Buy the eSIM and receive the QR code (usually by email or inside the provider's app). Some plans install directly from the app itself without scanning anything.
2. Install it by scanning the QR. On iPhone: Settings > Mobile Data > Add eSIM > Use QR Code. On Android: Settings > Connections > SIM manager > Add eSIM. Do it with a stable WiFi connection and do not close the screen until it finishes.
3. Set up the APN if instructed. Some eSIMs work on their own; others ask you to enter an access point name (APN) that the provider gives you. It is a value you copy exactly.
4. On landing in Japan, turn on data roaming on the eSIM line (not your home line) and choose it as the data line. In seconds you should have internet. Many eSIMs activate automatically on detecting the Japanese network.

The great advantage: when you step off the plane you already have data, with no shop to find, no queues and nothing to change physically. Your home SIM stays inside the phone, so you can keep your number working to receive bank SMS or calls (with voice roaming on, depending on your plan) while you browse with the eSIM.

With internet sorted on arrival, the next two steps of the first day are usually transport and money: setting up a Suica or Pasmo card for the metro and trains, and being clear on how much cash to carry per the money in Japan guide.

The million-dollar question. The good news is that in Japan you use less data than people expect, because free WiFi is very common: hotels, many cafes and restaurants, large stations and trains offer it. You use the eSIM mostly when you are out on the street.

The real consumption of a typical traveller goes almost entirely to three things: maps (Google Maps uses data while navigating), translator (Google Translate with the camera) and messaging (WhatsApp, LINE). That is light use. Consumption shoots up if you watch video, make long video calls or share the connection with other devices.

As general guidance, not an exact figure:

The eSIMs for Japan rely on the major local networks — mainly NTT Docomo, SoftBank and KDDI (au), the three operators with the widest coverage in the country — with 4G LTE and 5G depending on the area. Docomo has the greatest national reach; depending on the provider, your eSIM will use one of them or hop to whichever has the best signal at any moment. In practice, that translates into a very good connection in cities, transport and the vast majority of tourist areas.

Japan has excellent mobile coverage: cities, train lines (including much of the shinkansen), famous temples and common routes are well covered. The signal may falter, as in any country, in very isolated rural mountain areas or long tunnels, but for a standard trip through Tokyo, Kyoto, Osaka and surroundings it is not a problem.

The good

• You connect on landing: no queues, no paperwork and nothing to pick up at the airport.
• Everything from home: you buy and install it before leaving, at your ease with WiFi.
• You do not touch your home SIM: it stays inside the phone, so you keep your number for SMS and calls.
• Nothing physical to lose: no tiny card or router to charge and return.

The limitations

• It is usually data only: the tourist eSIM does not give you a Japanese phone number to make or receive local calls. To talk you use WhatsApp, LINE or FaceTime over data, which is the norm today.
• You need a compatible, unlocked phone: if your phone does not support eSIM, you will have to fall back on a physical SIM or pocket WiFi.
• It connects a single device: the eSIM is in your phone. If you travel in a group and want to share, you can use the phone as a hotspot, but there pocket WiFi is sometimes more convenient.

The eSIM market for Japan is very developed and there are several well-known providers — Holafly, Airalo, Ubigi, Saily, Nomad and others — besides the travel platforms that sell their own eSIMs. There is no single "correct" option: the best depends on your phone and your travel style.

Before choosing, look at four things:

• Type of plan. There are total-data ones (a bundle of GB for the whole trip, usually cheaper if you control your usage) and per-day quota or unlimited ones (you forget about calculating). Many "unlimited" plans have a fair-use policy: above a certain daily use they slow the speed, they do not cut you off.
• The network it relies on (Docomo, SoftBank or KDDI): any of the three gives you good coverage for a standard trip.
• Validity in days, which must cover your whole trip.
• Compatibility: that your phone supports eSIM and is unlocked.

A convenient route is to buy the eSIM on the same platform where you book activities and transport for the trip, so you have everything in one place, with clear instructions and, in many cases, free cancellation if you have not started using data. Whatever the provider, the pattern is always the same: you buy, receive the QR, install it before leaving and activate it on landing.