While Japan is considered to be a safe country by many measures, its unique geographic and climatic conditions make it prone to natural disasters, such as earthquakes, tsunamis and volcanic eruptions. As they are an essential lifeline, ensuring continuous connectivity for mobile services during large-scale disasters is critical.
While the five leading mobile carriers in Japan — NTT DOCOMO, INC., KDDI Corporation, Okinawa Cellular Telephone Company, SoftBank Corp. (TOKYO: 9434) and Rakuten Mobile, Inc. — have until now promoted landlines, public payphones and free Wi-Fi services, including "00000JAPAN," as alternative communication methods during such incidents, maintaining connectivity for customers without access to these alternatives has remained a significant challenge.
To ensure critical mobile communication remains available to people when they need it most, the five mobile carriers unveiled a nationwide emergency roaming service on March 18, 2026.
Carriers will provide alternative service using cross-carrier network access
The service, called “JAPAN Roaming,” will be available from April 1, 2026*¹ and enable users to temporarily connect to another carrier's 4G LTE network if their primary service is disrupted by large-scale disasters or major outages*².
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The service is provided based on coordination among the five mobile carriers in the event of a large-scale disaster or major network outage. It is not available during normal conditions or minor service disruptions.
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Some services may not be available while using "JAPAN Roaming". Please check each company's website for specific details.
The "JAPAN Roaming" service offers two distinct operating modes — Full Roaming Mode and Emergency Calls Only Mode — which will be activated by the five participating carriers based on the severity of the disaster, including the extent of network damage, the number of affected users and the overall status of communication infrastructure.
For more details and information on how to use the service, see this press release.
For further details regarding eligibility, compatible devices and usage with SoftBank Corp.’s mobile services, please visit the corresponding service website below (in Japanese):
'SoftBank' , 'Y!mobile' , 'LINEMO' , 'SoftBank for Business'
(From left) Representatives from the Telecommunications Carriers Association (TCA), NTT DOCOMO, KDDI, SoftBank and Rakuten Mobile gave a briefing about the "JAPAN Roaming" service on March 18, 2026
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(Posted on March 18, 2026)
by SoftBank News Editors
