NTT DoCoMo Inc. said Tuesday its international roaming services for subscribers traveling outside Japan were disrupted Monday evening, affecting its World Wing coverage area comprising 220 countries and regions.
DoCoMo, the nation's largest mobile carrier, experienced similar problems Aug. 2 and 3. While the prior trouble also triggered disruptions in domestic services, the latest interruption had not caused any impact domestically as of Tuesday.
Trouble with voice calls, email and Internet services started at 6:24 p.m. Monday Japan time and were continuing as of early Tuesday evening, DoCoMo said.
Its international circuits may have been overburdened by a rise in traffic volume and they also may have been affected by a rise in overseas travelers during the summer vacation season, DoCoMo said.
A total of 1,220 complaints or inquiries reporting bad connections and other troubles had been filed as of 5 p.m. Tuesday.
DoCoMo said its announcement came a day after the incident took place because the company was "hurrying to grasp the cause and take steps to restore services."
The company experienced service disruptions from summer last year until January this year, including email addresses switched with those of other people and voice call and data transmission troubles.
In January, the Internal Affairs and Communications Ministry ordered DoCoMo to prevent a recurrence of similar trouble.