eSIM for Spaniards traveling to Japan — Internet in Asia from Spain

In short: To travel to Japan from Spain, the most practical option is to activate a Japanese eSIM before you leave: you avoid expensive roaming charges from your Spanish operator and have data working as soon as you land, without touching any physical card and keeping your Spanish number for calls and SMS.

If you're planning a trip from Spain to Japan, you've probably already asked yourself the question: should I activate my operator's roaming, buy a physical SIM upon arrival, or set up a pocket wifi? There's a fourth option that, for the vast majority of Spanish travelers, is the most convenient and cheapest: an eSIM for Japan.

In this guide, we'll get straight to the point: what is the time difference between Spain and Japan, what are the flights like from here, how many GB do you need depending on your itinerary, how to activate the eSIM before boarding the plane, and what things will surprise you upon arrival that no generic Japan guide tells you.

Roaming from Spain to Japan: why it's expensive and what alternatives there are

Japan is not part of the European Union, so the "roaming like at home" flat rate does not apply. As soon as you land in Narita, Haneda, or Kansai, your Spanish operator will start charging you at non-EU roaming rates, which are significantly higher than your usual rate and, with most companies, are charged in limited bundles or by direct consumption. Costs quickly skyrocket if you use your mobile as you would in Spain: Maps all day, photos to family, an occasional video.

Before comparing, it's worth understanding exactly what roaming is and why it works this way: we explain it in detail in what data roaming is. And if you want to see a full roaming vs. eSIM comparison applied to any destination, we have a dedicated guide on eSIM vs. roaming.

The other classic option is to buy a physical Japanese SIM upon arrival, at the airport or at a store like Bic Camera. It works, but it means queuing as soon as you get off the plane, with jet lag and wanting to get to the hotel, losing your Spanish SIM while you use the Japanese one —unless you have a physical dual SIM, which is becoming less common— and depending on stock availability. An eSIM solves all three issues: no queuing, no losing your Spanish line, and bought from the comfort of your home.

Time difference and Spain-Japan flights: what changes compared to other trips

Japan is 8 hours ahead of Spain in winter time (CET) and 7 hours ahead in summer time (CEST), because Japan does not change its clocks throughout the year. This has a practical consequence that many people overlook: if you leave Madrid or Barcelona in the afternoon, you will land in Japan in the late afternoon/evening of the next day, with your body all out of sorts. Having active data from minute one helps more than it seems: you can let family know you've arrived safely, call a taxi, or find your hotel without relying on airport Wi-Fi, which might be saturated at those hours.

Another surprising detail: there are currently no direct flights between Spain and Japan. Flights involve a layover, usually in Helsinki, Paris, Amsterdam, Frankfurt, Munich, Istanbul, Doha, or Dubai, a long journey with transit through a third country where you won't have data either. Installing the Japanese eSIM at home, with Wi-Fi, before heading to the airport saves you from relying on the coverage at that layover to get everything ready.

How an eSIM for Japan works (for those who have never used one)

An eSIM is a digital SIM card integrated into the phone itself: there's nothing physical to insert or remove. It's installed by scanning a QR code and, from that point on, your phone can have both your Spanish line (for calls and SMS) and your Japanese eSIM line (for data) active simultaneously, switching between them without touching anything physically.

In practice, the process is as follows:

1. Buy the data plan for Japan at purasim.com before leaving Spain.
2. You receive the QR code by email.
3. Scan it from home, with Wi-Fi, and the profile is installed on your phone (this doesn't consume data or start the plan's countdown).
4. Upon landing in Japan, activate the eSIM's mobile data from your phone settings.
5. Your Spanish line remains active in parallel for calls and SMS.

If you've never installed an eSIM and want a step-by-step guide with screenshots for iPhone and Android, you can find it in how to install an eSIM. If you're weighing between an eSIM and an international physical chip, we explain the detailed comparison in another guide dedicated to that decision.

How many GB you need for Japan according to your trip type

There isn't a single number that works for everyone: it depends on whether you're taking an urban getaway to Tokyo or a long route crossing the country by shinkansen. As a guide, this is how we usually advise travelers departing from Spain:

Actual consumption depends heavily on whether you use Google Maps with constant turn-by-turn navigation (this uses more data than people realize, especially in Japanese cities, where intersections and subway exits are a maze) or if you only check it occasionally. If your plan runs short halfway through your trip, you can always top up data without losing your number or reinstalling anything. And if you want to extend the plan you bought, we have specific —not generic— tips for saving data in how to save data with an eSIM while traveling.

How to activate the eSIM before your flight from Spain

Ideally, everything should be set up calmly at home, not at the boarding gate with the airport Wi-Fi saturated. The complete process:

1. Check that your phone supports eSIM. Most iPhones from the XS onwards, Samsung Galaxy mid-to-high range from the S20, and Google Pixel from the 3 support it, but there are exceptions depending on the model and, in some cases, whether the phone is unlocked or tied to a specific Spanish operator. Check your phone settings before purchasing.
2. Purchase the data plan for Japan at purasim.com, choosing the duration and GB according to the table above.
3. Install the profile from the email with the QR code, with your phone connected to Wi-Fi at home. This does not activate the plan yet.
4. Set the eSIM as "data only", not as the primary line, so that calls and SMS continue to go through your Spanish number.
5. Activate it upon landing, by turning on the mobile data for that line from your settings. You'll have coverage in a couple of minutes.

A detail that is not usually mentioned: installing the profile does not start the plan's clock. The countdown begins with the first actual use of data on the Japanese network, so you can install it days in advance without fear of "wasting" travel days upfront.

Roaming, eSIM, physical SIM, or pocket wifi: quick comparison

Things that will surprise you in Japan (and that you should know before landing)

Beyond connectivity, there are a number of specific details about Japan that are not in the standard tourist guide and that directly affect how you will use your mobile there:

• Free Wi-Fi at konbini (7-Eleven, FamilyMart, Lawson) is not reliable as a primary plan. It usually requires email registration for each different network and you have to reconnect every few hours. It's fine as occasional support, not as your travel connection.
• LINE, not WhatsApp, is the app Japan uses. Many restaurants and small accommodations manage reservations via LINE, not by phone or WhatsApp. It's worth having it installed, even if your home group is still on WhatsApp via the eSIM.
• You'll lose signal for a few seconds in shinkansen tunnels. This is normal and will recover automatically when you exit; it's not an eSIM fault.
• Mountain areas and onsen towns have weaker coverage. In Hakone, around Fuji, or in rural Tohoku towns, the signal drops outside urban centers. Download an offline map before leaving the big city.
• Notify your Spanish bank before you leave. Many banks flag purchases in Japan as suspicious if they haven't been notified, just when you're buying a train ticket or your first dinner.
• The JR Pass and many shinkansen reservations are managed through apps or websites, not just at the ticket counter. Having data allows you to book without relying on station Wi-Fi, which can be slow during Tokyo's peak hours.

Myths and common mistakes about eSIM in Japan

There are several circulating ideas about eSIMs in Japan that don't quite align with reality:

• "If I have roaming in the EU, it will also work the same in Japan." No. The EU roaming flat rate only applies within the European Union. In Japan, you revert to your operator's international roaming conditions, which are a completely different story.
• "The more GB I buy, the better, just in case." Not necessarily: if you overestimate a lot, you pay for data you won't use. It's better to calculate according to the table above and top up on the go if necessary, which you can do without leaving your active plan.
• "The eSIM takes time to activate upon arrival." If you installed it at home before leaving, activation upon landing is a matter of seconds: you are simply turning on mobile data for a profile that is already installed, not downloading anything new.
• "I need to deactivate my Spanish SIM for the eSIM to work." On the contrary: the beauty of it is having both active at the same time, each with its function (data via eSIM, calls and SMS via your Spanish line).
• "Coverage in Tokyo is uniform everywhere." Within the city, coverage is solid, but in deep subway basements, some very large shopping centers, or areas with concentrated skyscrapers, there may be spots with weaker signal, as happens in any major city in the world.

When you DON'T need to buy an eSIM for Japan

Being honest about this builds more trust than selling you something you don't need. There are situations where an eSIM doesn't make sense:

• If you're only making a technical layover at Narita or Haneda without leaving the airport. The airport's free Wi-Fi is sufficient for those few hours; you don't need mobile data.
• If your phone doesn't support eSIM. Some older models or certain carrier-locked versions don't support it. In that case, a Japanese physical SIM or a pocket Wi-Fi are your real alternatives; don't force an eSIM on a phone that doesn't support it.
• If you're staying your entire trip at a single hotel-resort with reliable Wi-Fi and won't be exploring on your own (uncommon in Japan, but exists in very structured packages), the savings margin is smaller because you'll barely need data outside the accommodation's Wi-Fi.

Outside of these specific cases, for the vast majority of trips from Spain to Japan—where you'll be moving around, browsing, booking on the go, and wanting to contact home—the eSIM remains the most practical option compared to roaming.

If your trip doesn't just stay in Japan and you're combining it with South Korea, there's a combined plan in eSIM Japan and South Korea, and if you also pass through China, there's a three-country version in eSIM China, Japan, and South Korea. If your Asian route includes Seoul or Busan as a separate destination, the specific guide is in eSIM for South Korea: Seoul and Busan.

Frequently asked questions about eSIM for Japan from Spain

Can I still use my Spanish number while the eSIM is active in Japan?

Yes. The eSIM occupies an independent line within the same phone. Your Spanish number continues to receive calls and SMS normally; only data goes through the Japanese line. To call Spain without international call charges, use WhatsApp, LINE, or FaceTime via that data connection.

How long does the eSIM plan last once I buy it?

It depends on the plan you choose (e.g., 7, 10, 15, or 30 days). The important thing is that the countdown does not start when you install the profile, but with the first actual use of data in Japan, so you can install it in Spain with plenty of time without losing days of coverage.

Can I buy the eSIM while already in Japan if I forgot to do it before leaving?

Yes, as long as you have Wi-Fi access (hotel, airport, or a konbini). It installs the same way, in a few minutes. However, it is more convenient to get everything done before leaving Spain so you don't have to rely on finding Wi-Fi as soon as you land.

Does the PuraSim eSIM for Japan include calls and SMS?

No, it's a data-only plan. For calls and SMS, both local in Japan and to Spain, use your usual Spanish line or apps like WhatsApp, LINE, or FaceTime via the eSIM's data connection.

Does the eSIM work on the shinkansen and in rural areas of Japan?

Yes, with the same coverage as any local Japanese line: good on main shinkansen lines and in cities, with occasional cuts when passing through tunnels and weaker signal in mountainous areas or remote villages, where it's advisable to have an offline map downloaded just in case.

What is the time difference between Spain and Japan, and does it affect activation?

Japan is between 7 and 8 hours ahead of Spain depending on the time of year, as there is no seasonal time change there. It doesn't affect the eSIM activation itself, but it is useful to keep in mind to let family know of your arrival as soon as you land, which you can do instantly if you already have active data.

What should I do if the eSIM doesn't connect when I arrive in Japan?

First, check that you have activated mobile data for that specific line (not just installed the profile) and that network selection is set to automatic in your settings. If it still doesn't connect, PuraSim support is available to help you with your order number handy.

Written by Marc González Sáez Founder of PuraSim and a specialist in eSIM and connectivity for travelers. He has been helping people travel connected worldwide for years without overpaying for roaming, and personally tests eSIMs in each destination before recommending them.