If buying a prepaid data SIM or eSIM in Japan has felt like the one part of “getting set up” that didn’t ask for much ID, that’s about to change. Japan’s Diet passed a revision to the 携帯電話不正利用防止法 (Mobile Phone Improper Use Prevention Act) in 2026, aimed squarely at the anonymous SIM cards that have been fueling scam-call and fraud networks. Two things are happening: identity verification for regulated SIMs is moving to a harder-to-fake method, and data-only SIMs — the kind most tourists and short-term visitors buy — are being pulled into scope for the first time. Here’s exactly what’s confirmed, what’s still being finalized, and what it means the next time you buy a SIM in Japan.
📋 Quick Navigation: What’s confirmed · What’s still being finalized · What to actually do · FAQ
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What’s confirmed about Japan’s SIM ID law changes
- The law passed in 2026. The revised Mobile Phone Improper Use Prevention Act was enacted by Japan’s Diet in 2026, explicitly targeting fraud rings that use anonymous SIM cards for scam calls and phishing.
- Verification method upgraded (from around April 2026): For SIM contracts already requiring ID, carriers are moving away from customers simply uploading a photo of their ID. The new standard reads the IC chip embedded in a My Number Card, driver’s license, residence card, or special permanent resident certificate — a method that’s far harder to spoof with a doctored photo.
- Data-only SIMs are newly in scope. Data-only plans (no voice, no SMS) — historically exempt from identity-verification rules — are being brought under the law for the first time. This closes the loophole that let scammers buy data SIMs anonymously.
- Penalties are real: Carriers that fail to comply face administrative orders, business restrictions, and criminal penalties of up to 2 years imprisonment or a ¥3 million fine; submitting fraudulent ID is itself a criminal offense.
What’s still being finalized
In the interest of not telling you something that turns out to be wrong: the government has confirmed the direction but has not yet published a single fixed enforcement date for the data-SIM provision specifically, and a cap on how many lines one person can hold is referenced in the law as a concept (“an abnormally high number of lines”) without a concrete number yet attached. Carriers are expected to start requiring ID for data SIMs progressively as the ministerial ordinances are finalized, and some are already asking for passport ID at point of sale ahead of the formal deadline. We’ll update this post with the exact date once it’s officially confirmed — treat any specific date you see elsewhere with caution until it’s on an official MIC (Ministry of Internal Affairs and Communications) notice.
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What to actually do when you buy a SIM in Japan now
- Carry your passport (tourists) or residence card (residents) whenever you buy a SIM — airport counters, konbini, or electronics stores — even for a “data-only” plan. Some carriers are already asking ahead of the formal deadline.
- Residents: if you’re registering a plan under a My Number Card or driver’s license, having the physical card on hand (not just a photo of it) will matter more under the new IC-chip verification method.
- Don’t buy or use unregistered/anonymous SIMs from resale sources — this is exactly the activity the law targets, and using one could leave you holding a line that gets cut off without warning.
- Keep your purchase receipt and registration confirmation until you’re sure the SIM is fully active, in case a carrier asks for a follow-up verification step during the transition.
Japan SIM Card ID Law 2026 FAQ
- Do I need ID to buy a data-only SIM in Japan right now? Requirements are tightening and some carriers already ask for ID, but the government has not yet published one fixed enforcement date for the data-SIM provision — expect it to apply broadly as 2026 progresses.
- What ID counts for the new verification method? My Number Card, driver’s license, residence card, or special permanent resident certificate (IC-chip read) for residents; passport for tourists and short-term visitors.
- Were data-only SIMs really unregulated before? Yes — the Mobile Phone Improper Use Prevention Act historically applied only to voice/SMS-capable SIMs, leaving data-only SIMs outside its scope.
- What happens if a carrier doesn’t comply? Administrative orders, business restrictions, and criminal penalties of up to 2 years imprisonment or a ¥3 million fine for the carrier.
- Is there a limit on how many SIM lines one person can have? The law references limiting an “abnormally high number of lines,” but a concrete numeric cap has not yet been finalized.
- Does this affect eSIMs the same way as physical SIMs? The law targets the underlying mobile line contract, not the physical form factor, so eSIM data plans are expected to fall under the same verification requirements as physical data SIMs.
Quick reference
- Law enacted: 2026, by Japan’s Diet
- Verification method upgrade: IC-chip reading replaces photo-upload ID (from around April 2026)
- Newly in scope: Data-only SIMs and eSIMs (previously exempt)
- Not yet finalized: Exact enforcement date for the data-SIM provision; numeric cap on lines per person
- Action: Carry your passport or residence card whenever you buy any SIM, including data-only plans
- Related: Setting Up Life in Japan: Bank, SIM, Health Insurance & Residence Card | Best Apps for Living in Japan 2026 | TIFE for Travelers
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