KDDI Corporation - Total telecommunication service provider in Japan. KDDI, a leading Japanese telecommunications company contributes to create better society through its ICT technology. More than 45 million subscribers enjoy KDDI's advanced telecommunication service through mobile phone and other ... KDDI Corporation - Total telecommunication service provider in Japan. KDDI, a leading Japanese telecommunications company contributes to create better society through its ICT technology. More than 45 million subscribers enjoy KDDI's advanced telecommunication service through mobile phone and other ...