Japan has some of the world’s fastest and most reliable mobile networks, but local carriers rarely sell short-term tourist plans directly. Most visitors use a prepaid tourist SIM or — increasingly — an eSIM they install before arrival, so they are online the moment they land.
Networks & coverage
Three operators run the physical networks: NTT Docomo (the widest rural and mountain coverage), SoftBank, and au by KDDI; Rakuten Mobile is a newer fourth network, strongest in cities. Travel SIM and eSIM brands such as Airalo, Ubigi and Holafly resell capacity on Docomo or SoftBank. 4G LTE is effectively nationwide — including Shinkansen routes and rural onsen towns — while 5G is live across Tokyo, Osaka, Kyoto, Nagoya and other major cities and is expanding quickly.
eSIM or physical SIM?
If your phone supports eSIM (iPhone XS and newer, most recent Pixel and Galaxy models), an eSIM is the simplest choice: buy online, install before you fly, and activate on landing. Physical tourist SIMs are sold at arrivals counters in Narita, Haneda and Kansai airports and at electronics chains like BIC Camera and Yodobashi Camera. Check that your handset is carrier-unlocked before you travel.
Data, calls & messaging
Most tourist SIMs and eSIMs are data-only and do not include a Japanese phone number — use LINE, WhatsApp or FaceTime over data for calls. If you need a local number (for restaurant bookings or SMS verification), Mobal and Sakura Mobile sell voice-capable visitor SIMs. LINE is the dominant messaging app in Japan, so install it before you go.
How much data do you need?
As a rough guide: 1 GB suits a few days of light maps and messaging, 3–5 GB is comfortable for a one-to-two-week trip, and an unlimited plan is worth it for heavy navigation, tethering or video. Travelling as a group? A single unlimited eSIM with hotspot, or a pocket Wi-Fi rental, can work out cheaper than one SIM per person.