KDDI Corp., taking full advantage of the number portability system, said Wednesday that it added a net 249,400 new subscribers in April compared with only 65,800 for NTT DoCoMo Inc., the nation's largest mobile phone operator.
April is one of the busiest months for mobile phone campaigns because it marks the beginning of both the new business year and new school year.
Under number portability, introduced last October, customers can retain their original phone numbers even when switching service providers.