Internet and Mobile Data in Japan: SIM, eSIM and Pocket Wi-Fi

In Japan your phone is your map, your translator, your train timetable and often your menu. Staying connected is not a luxury, and it is also one of the first things Portuguese travellers worry about, because there are five ways to do it and none is best for everyone. This guide compares them by what matters when you choose: your phone, your group, how much you will use it and how much hassle you can take. It does not push one provider. Anything that can change is dated: we checked the pages mentioned on 21 October 2026.

The short answer

• Most Portuguese travellers with a recent, unlocked phone: a data eSIM. It is installed before you fly and starts working on landing.
• Families, groups and older phones: a pocket Wi-Fi router. One device can serve several phones and it does not depend on your phone supporting eSIM.
• Want a Japanese phone number: this is hard for a short visit. Tourist SIMs are generally data-only, because a voice number normally needs proof of residence or ID checks. Use messaging apps for calls instead.
• Roaming with your Portuguese operator: simple but usually the most expensive way. Compare the price before you rely on it.
• Free Wi-Fi only: fine as a backup, not as a plan.

The five options compared

We cover eSIMs only at overview level here. For how to choose a plan, check your phone and install it step by step, read our dedicated guide to eSIM for Japan from Portugal: how to choose and set up.

What you actually use data for in Japan

• Google Maps and transit apps: routes, platform numbers and walking directions. This is the biggest daily use.
• Translation and camera translation: a menu or sign photographed and translated on the spot. See our guide to translating Japanese from a photo.
• QR-code menus and restaurant booking pages.
• Messaging and calls over WhatsApp, Messenger or similar apps, and photo uploads.
• Hotel check-in emails, booking confirmations and tickets stored online.
• IC card top-up and wallet apps, where a connection helps.

See how the transport card works in our guide to IC transport cards in Japan: Suica, Pasmo and ICOCA, and how to translate a sign or menu in translating Japanese from a photo.

How much data do you need a day?

These are our own rough ranges, not figures from a provider, so treat them as a starting point. Streaming video and uploading lots of photos push you well above them.

A plan with a daily cap that slows down after a limit is often easier than a fixed total for the whole trip, but read the terms. Add a margin for the first and last days, when you arrive and download maps.

Check your phone first

• Unlocked: a phone tied to a Portuguese operator contract may refuse a foreign SIM or eSIM. Ask your operator whether it is unlocked and, if not, how to unlock it, well before you travel.
• iPhone: look in Settings, General, About for a line labelled Digital SIM or EID. If it is there, the phone supports eSIM. Check the same screen for any carrier lock message.
• Android: look in Settings, About phone for an EID or a SIM manager that offers to add an eSIM. Menus vary between brands, so search the settings for eSIM or SIM.
• Dual SIM: if the phone can run a Portuguese SIM and a data eSIM together, you keep your normal number reachable while using local data.
• Software updates: install them at home, not in the arrival hall.

eSIM, in brief

An eSIM is a digital SIM that you install by scanning a QR code or following an app. It is usually the cheapest and most convenient choice for a recent phone and a short trip. The trade-offs are the phone requirement above and the fact that most tourist eSIMs are data-only. Install it on Wi-Fi at home, keep your Portuguese line on for messages, and turn on the new data plan when you land. The details, including what to compare between providers, are in our eSIM guide linked above.

Physical tourist SIM

• Where to buy: airport counters and vending machines, and electronics shops such as BIC Camera and Yodobashi Camera. You can also buy online before you go and collect or receive it.
• Your phone must be unlocked, and you need to swap the SIM and often enter network settings (APN) by hand.
• Keep your Portuguese SIM safe in a small case or the original holder. It is tiny and easy to lose, and it carries your bank and messaging number.
• Tourist SIMs are normally data-only. A SIM with a Japanese voice number needs identity checks that short-stay visitors usually cannot complete, which is why voice SIMs are hard to get.
• Good for phones without eSIM, but slower to set up than an eSIM and tied to the opening hours of the shop.

Pocket Wi-Fi

• How it works: you rent a small router online, collect it at an airport counter or have it sent to your hotel, and return it by post in a prepaid envelope or at the airport.
• One router can connect several phones, laptops and tablets at the same time, which is why it suits families and groups.
• It is charged by the day, so a longer trip costs more per day than an eSIM for one person, but a group splits the cost.
• Battery life is limited, often a full day of use but not always more. Carry a power bank and charge it at night.
• Everyone has to stay near the person carrying it; if you split up, one of you has no internet.
• Return it on time. Late fees and missing items are charged, and you may need to post it from the last hotel or the airport.

The Japan National Tourism Organization (JNTO) describes pocket Wi-Fi as a safe option for guaranteed coverage, with rental desks at major airports or online reservation for delivery to your hotel. See the official page in the list at the end.

Roaming with a Portuguese operator

• Japan is outside the EU and EEA, so the EU rule that lets you use your plan abroad at no extra cost does not apply.
• Portuguese operators such as MEO, NOS and Vodafone sell roaming passes or data bundles for non-EU countries, or charge by usage. Terms and prices differ and change.
• We do not quote prices here. We checked the NOS roaming page on 21 October 2026: it says calls, SMS and internet outside the EEA are charged according to the country, promotes Net Roaming data packs and shows no Japan price. We could not fetch the MEO or Vodafone pages, so check your own operator's app or website for the current Japan offer.
• Switch data roaming off in your phone settings until you have decided. Leaving it on by accident is the most common cause of a surprise bill.
• Roaming is convenient if you want no setup at all, but it is usually the dearest of the five options for a week or more.

Free Wi-Fi

• Where: airports, stations, many hotels, some cafes such as Starbucks, and some convenience stores. Many ask you to register first.
• Japan Wi-Fi auto-connect apps can sign you in automatically, but check that the app still exists and what it collects before you install it. The JNTO news post about one of them dates from 2021.
• JNTO's page says the signal in cafes, fast food places and convenience stores can be patchy and slow.
• It is a backup, not a plan. You will lose the connection between places and when you need a map most.
• Do not do banking or enter passwords on a public network unless the site is secure and you trust the network.

Convenience stores often have a Wi-Fi sign, but registration and speed vary. See our comparison of 7-Eleven, FamilyMart and Lawson for what each chain offers a traveller.

Keep WhatsApp and SMS codes working

• WhatsApp and similar apps work over any data connection, so your eSIM, SIM, router or Wi-Fi will carry them. Your account stays on your Portuguese number.
• Bank and login codes by SMS go to your Portuguese SIM. With the SIM on and data roaming off, incoming SMS usually still arrives, but this depends on the operator and can cost a small fee.
• Check with your operator before you go whether you can receive SMS abroad and what it costs.
• If your bank offers app-based approval, set it up before you travel, as it does not rely on SMS.
• If you swap to a physical SIM, you lose SMS on your Portuguese number unless the phone has a second slot or eSIM.

A simple decision flow

• Does your phone support eSIM and is it unlocked? If yes, go to step 2. If no, go to step 4.
• Are you travelling alone or as a pair, with phones that both support eSIM? If yes, choose a data eSIM and install it at home.
• Are you a family or group that wants one connection, or do you need a laptop online? Choose a pocket Wi-Fi.
• Is the phone unlocked but without eSIM? Buy a physical tourist SIM, or rent a pocket Wi-Fi if you would rather not swap SIMs.
• Is the phone locked? Ask your operator to unlock it, or rent a pocket Wi-Fi.
• Want a Japanese number? Accept data-only and use messaging apps, or check a provider's terms carefully for identity requirements.
• Whichever you pick, save a map area offline and keep roaming off as a backup.

Japanese words for Wi-Fi and signal

If you have an emergency and need help, a phone connection matters. See our Japanese emergency numbers and phrases and save them offline.

Official information

Pages we fetched and read on 21 October 2026:

• JNTO, Wi-Fi in Japan: confirms free Wi-Fi at major airports, a SoftBank free passport for foreign phones, patchy free Wi-Fi in cafes and convenience stores, pocket Wi-Fi rental at airports or online, SIM cards at airports and at stores such as BIC Camera and Yodobashi Camera, and that a phone must be unlocked to use a SIM. It does not mention eSIM or say whether SIMs are data-only.
• NOS roaming page: confirms that outside the EEA usage is charged by country and that Net Roaming packs exist. It shows no Japan prices on the page.

Sources: JNTO: Wi-Fi in Japan and NOS: roaming. Providers, plans and prices change, so check the current terms before you buy. We could not fetch an official MEO or Vodafone Portugal roaming page, so we cite none.