Japan Law Changes in May 2026: Complete Roundup of New Statutes Taking Effect

The April–May 2026 window has brought one of the largest waves of statutory reform in Japan's postwar history. This article catalogs the major laws taking effect (or whose enforcement is imminent) and outlines key compliance points across family, labor, traffic, corporate, and criminal law.

Japan's revised Civil Code (Act No. 33 of 2024) introduced opt-in joint custody after divorce. One month into enforcement, family courts are already seeing a sharp rise in joint-custody related mediation filings.

Key provisions include mandatory sole custody where domestic violence is present, and a new statutory child support floor of ¥20,000 per child per month.

Amendments to the Comprehensive Labor Policy Promotion Act will require all employers to implement customer-harassment prevention measures. Many large companies are already revising HR rules and response manuals during the lead-up.

Employers must offer flexible work arrangements (shortened hours, telework) to employees raising children under three.

The income threshold above which short-hour workers must enroll in social insurance is being phased out, with significant cost implications for retail, food service, and other industries with many part-time staff.

After 18 months in force, administrative guidance is now being issued for violations of the written-terms requirement and 60-day payment rule. Hiring companies should re-audit their contracts.

Cyclists aged 16+ are now subject to traffic-infraction tickets, with fines ranging from ¥5,000 to ¥12,000 for offenses such as red-light running, phone use, and cycling under the influence. The National Police Agency reports approximately 8,000 tickets nationwide in the first month.

Local roads without center lines now have a statutory maximum speed of 30 km/h. Fleet operators must update driver guidance.

Motorcycles between 51cc and 125cc can now be operated under a moped license if they meet new performance restrictions, expanding rider options.

Grace periods for the electronic preservation of digital transaction records have ended. Continuing to rely on paper or non-compliant electronic storage exposes companies to revocation of the blue tax return privilege and back taxes.

The transitional 80% input-tax credit for purchases from tax-exempt businesses expires September 30, 2026, dropping to 50% thereafter. Companies should accelerate negotiations with suppliers about taxable-status conversion.

The Japan Fair Trade Commission has tightened price pass-through guidelines, increasing scrutiny of abuses of superior bargaining position. Documenting contract terms is essential.

The newly created cannabis use offense drove drug-related arrests to a record 6,000+ in 2025. Trends in suspended sentencing for first-time offenders are being closely watched.

Undercover identity operations and role-play investigations are now part of the police toolkit against organized fraud and recruited-criminal schemes.

Following the Hakamata case, the Diet is considering a Criminal Procedure Code amendment that would impose a one-year deadline on prosecutorial appeals of retrial orders.

The Supreme Court's Third Petty Bench referred six same-sex marriage cases to the Grand Bench. A first-ever Japanese Supreme Court constitutional ruling on same-sex marriage is expected by early 2027.

Issuance of conventional health insurance cards stopped in December 2024, and grace-period expirations are now reaching medical providers in earnest.

1. Review HR rules and policies (customer-harassment, parental leave, part-timer enrollment)
2. Update contract templates (Freelance Protection, Subcontract Act)
3. Audit electronic recordkeeping systems
4. Run employee training (harassment, compliance, drug awareness)
5. Revisit invoice-system supplier strategy before the October 2026 credit reduction

April and May 2026 mark the most concentrated wave of statutory enforcement Japan has seen in a decade. Companies should audit their HR, legal, and accounting functions concurrently. For specific provisions, see our dedicated articles on each topic.

For tailored advice, please consult with a qualified attorney.