Prepaid SIMs are SIM cards with pre-paid usage for set periods or data amounts. No monthly contracts needed - use until depleted (or recharge). Ideal for travelers, short-term visitors, and secondary lines.
In Japan, prepaid SIMs are available at airport vending machines, convenience stores, and electronics retailers. Tourist data-only SIMs cost 1,000-3,000 yen for 7-30 days with 1-10GB. Voice-capable prepaid SIMs require identity verification under the Criminal Proceeds Act.
Caveats: data-only SIMs without 050 numbers or voice can't make emergency calls (110/119). Some lack SMS capability, preventing OTP reception.
Criminally, loosely verified prepaid SIMs are exploited as "burner phones" for special fraud. 2024 amendments mandated strict identity verification for prepaid SIM sales. See phone number privacy.