Compare Mobile SIMs in Japan

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31 live offers compared from 13 providers, from ¥100 /month. Updated daily.

What are mobile SIMs in Japan?

Mobile SIMs in Japan cover the plans that connect your phone to a network, sold either by the three major carriers, their low-cost sub-brands, or independent MVNOs (kaku-yasu SIM, or budget SIMs) that resell network capacity. The market shifted sharply toward value after regulators pushed carriers to unbundle handsets and simplify pricing, and eSIM and online-only signup are now widespread.

How the Japanese market works

At the top are docomo, au and SoftBank, complemented by their online and value sub-brands — ahamo (docomo), povo (au), LINEMO (SoftBank), plus UQ Mobile and Y!mobile. Rakuten Mobile competes as a fourth network with simple all-in pricing. Independent MVNOs such as IIJmio, mineo, BIGLOBE Mobile and OCN Mobile lease capacity from the big networks and undercut them on price, targeting light-to-moderate data users.

Benefits

Low monthly cost — budget SIMs and sub-brands slash bills, with small-data plans available for very little and some promotions near zero.

Flexible data tiers — plans scale from a few gigabytes to unlimited, so you pay for what you actually use.

eSIM and easy switching — number portability and eSIM let you change providers quickly, often entirely online.

How to choose

Estimate your monthly data use first: MVNOs like IIJmio and mineo win for light users, while Rakuten Mobile or an unlimited sub-brand suits heavy users. Compare price at your data tier, network quality where you live and commute, whether calls are bundled or charged per minute, and speed at peak times — MVNOs can slow at midday. Confirm eSIM support and any contract or MNP (number-portability) fees before switching.

Leading providers in Japan

docomo, au and SoftBank run the core networks, with ahamo, povo and LINEMO as their online-only value tiers and UQ Mobile and Y!mobile as mid-price sub-brands. Rakuten Mobile offers straightforward tiered-to-unlimited pricing on its own network. IIJmio, mineo, BIGLOBE Mobile and OCN Mobile lead the independent budget-SIM segment.

What it costs

Prices span from effectively ¥0 on some promotions and tiny-data budget plans up to around ¥3,000 for mid-tier data and toward ¥7,000 to ¥14,800 for premium unlimited or device-bundled plans. Budget SIMs cluster at the low end, sub-brands in the middle, and full carrier plans at the top. Watch for one-off SIM issuance or MNP fees and any minimum-use period.

Protections and regulation

Mobile services are regulated by the Ministry of Internal Affairs and Communications (MIC), whose Telecommunications Business Act reforms curbed excessive handset subsidies, capped cancellation penalties and improved price transparency. Consumers benefit from clearer plan disclosure and easier number portability. Identity verification is required at signup under anti-fraud rules.

Common questions

Are budget SIMs reliable? Yes — MVNOs use the same underlying docomo, au or SoftBank networks, though speeds can dip at busy times like the lunchtime peak.

Can tourists buy a SIM? Long-term residents need a residence card for most plans, but travel and prepaid data SIMs and eSIMs are widely available for short visits.

Mobile SIM Plans in Japan — FAQ