Buy a Japan eSIM Online

Mobile internet, 4G and 5G in Japan

Japan has four mobile networks: NTT DOCOMO, KDDI, SoftBank and Rakuten Mobile. The 2025 white paper from Japan's Ministry of Internal Affairs and Communications (MIC) ranks them by subscription share: DOCOMO 34.2%, KDDI 27.1%, SoftBank 19.1% and Rakuten Mobile 3.2%, with the KDDI figure taking in Okinawa Cellular and UQ Communications. Rakuten Mobile is the youngest of the four and by far the smallest; the other three carry most of the Japanese market between them.

On 5G, Japan is one of the best-documented markets anywhere, because MIC publishes the figures itself. The four networks together reach almost the entire population, and that coverage grew again between March 2023 and March 2024. One caveat belongs with it, and MIC puts it in a footnote of its own: this is the overlapping coverage of four operators added together. What a single network — and so a single SIM — delivers sits below that. In practice: 5G in and around the cities, with 4G taking over where 5G does not reach.

Roaming in Japan without an eSIM

Japan falls outside 'Roam Like at Home'. That European arrangement covers the 27 EU member states plus Iceland, Liechtenstein, Norway, Moldova and Ukraine — Japan is not on the list. Your Belgian or Dutch plan therefore does not travel with you: your operator bills Japanese data at its own out-of-bundle rate, and the European price caps that apply inside the zone do nothing here. The European Commission puts it plainly: roaming outside the EU and EEA can be expensive, and you are better off asking your own provider what it costs before you leave. In Japan the meter runs fast, because Japan is exactly where you use data — train times, maps, translation apps.

Internet for visitors in Japan: wifi, prepaid and identity checks

Getting online in Japan is not hard, and it would be dishonest to pretend otherwise. SoftBank alone offers visitors a full package: a prepaid travel SIM, a Free Wi-Fi Passport and the Japan 2 Go! programme. The friction is in the paperwork around it. Japan has a law on identity verification for mobile subscriptions, and an amendment to it was enacted on 22 May 2026. MIC has delegated the details to ministerial ordinances and publishes those materials in Japanese only. What a foreign visitor has to produce at the counter is therefore written down nowhere in English. An eSIM installed before departure never reaches that counter.