New subscriptions to NTT DoCoMo's mobile phone service in November were outnumbered by cancellations by 17,500 subscribers, the first-ever net decrease in the company's subscriber numbers, a Kyodo News report said.
Japan's biggest mobile phone operator blamed the outcome on a flight of subscribers to rivals, following the introduction of number portability on October 24, the Kyodo report said.
In separate announcements the same day, rivals KDDI and Softbank Mobile reported net gains of 324,900 and 68,700, respectively, in subscriber numbers in November, the report further said.
Number portability, which allows mobile phone users to keep their numbers when switching operators, benefited KDDI, which scored a net increase of 217,500 subscribers.
Cancellations outnumbered new subscriptions by 160,000 for NTT DoCoMo and by 53,900 for Softbank Mobile, the report said.
Softbank Mobile, despite the adverse effect of the portability system, posted a net increase in the overall number of subscribers as it won new corporate subscribers each using a large number of phones.
Meanwhile, some 680,000 subscribers, or only about 0.7% of all 94 million subscriptions, switched mobile phone operators by the end of November under the number portability system, the report added.