Do you need an eSIM in Japan?
Free Wi-Fi in Japan is easy to find in hotels, stations and convenience stores, but patchy in between. You'll want data on the move for train routes, maps, translation apps and restaurant bookings. A travel eSIM gives you that from the moment you land, without hunting for a SIM counter at the airport.
Which networks Japan eSIMs use
Japan has three main networks: NTT Docomo, KDDI (au) and SoftBank, plus the newer Rakuten Mobile. Travel eSIMs connect through one or more of them, and providers name the network in the plan details.
All three main networks cover the cities well. If you're heading to the mountains or rural areas, a plan that can use more than one network gives you the best chance of a signal.
How much data you need
For a week of maps, train routes, translation and social media, 5–10 GB is enough for most people. If you'll stream video, make video calls or share data with a laptop, look at unlimited plans. Our data guide has daily figures.
Unlimited plans: check the daily limit
Most "unlimited" plans slow down after a set amount each day. At the time of writing (November 2026), these were the providers' general rules:
- Nomad: 2 GB a day at full speed, then 1 Mbps.
- Airalo, Jetpac, aloSIM and Roamless: 3 GB a day, then 1 Mbps.
- GigSky: 3.5 GB a day, then 500 kbps.
- Saily: 5 GB a day, then 1 Mbps.
- Holafly: unlimited data, but hotspot is limited to 1 GB a day.
At 1 Mbps, maps and messages still work, video doesn't. Limits change, so check the plan page before you buy.
Phone numbers
Most travel eSIMs for Japan are data only, so you won't get a Japanese phone number. Use WhatsApp, or LINE, the most popular messaging app in Japan, for calls and messages. Keep your home SIM on, with data roaming off, to receive texts and bank codes.
When to install
Install the eSIM at home on Wi-Fi, a few days before you fly, and switch it on when you land at Narita, Haneda, Kansai or any other airport. Most plans start counting days when they first connect in Japan. Our guides cover iPhone and Android.
Which plan to pick
- A short trip, light use: a small fixed-data plan, 3–5 GB.
- One to two weeks, typical use: around 10 GB, or unlimited if you'll use a hotspot.
- Japan and other countries in Asia: compare a regional Asia plan with two country plans; the regional one is often cheaper.
Compare every Japan eSIM plan, sorted by price, price per GB or data.
Quick answers
Does a Japan eSIM work on the Shinkansen? Mostly, yes. Expect short drops in long tunnels.
Can I keep using my home number? Yes. Your home SIM stays in the phone. Leave its data roaming off so you're not charged.
Can I top up? It depends on the provider. Airalo, Saily, Nomad, Ubigi, Jetpac and GigSky let you add data to the same eSIM.