KDDI Corporation (commonly known as KDDI(au)) is a mobile network operator in Japan assigned PLMN code 440-51 by the national telecommunications authority.

The MCC 440 identifies Japan, while MNC 51 uniquely identifies this operator within the country. Together they form the PLMN (Public Land Mobile Network) identifier used by mobile devices for network selection, SIM card identification, and international roaming.

This assignment was last reported in ITU Operational Bulletin #1280 (Nov. 15, 2023). Search all MCC/MNC codes or view all Japan operators .