Japan’s early warning system: The role of mobile network operators

This report outlines Japan’s multi‑hazard early warning system, emphasising how mobile network operators support rapid, authoritative alerts for earthquakes, tsunamis and severe weather. It summarises Japan’s risk context, governance arrangements, regulatory frameworks and the technical design of J‑Alert, L‑Alert and ETWS.

Developed for policymakers, disaster management authorities, MNOs and humanitarian partners, the publication distils ten practical considerations for strengthening early warning systems, including clear governance, interoperable standards, robust public–private collaboration and diversified alerting channels. It stresses the need for redundancy, handset compatibility, regular testing, public awareness and sustainable financing to ensure reliability and public trust. These lessons offer actionable guidance for countries seeking to expand early warning coverage and align with the Early Warnings for All initiative.