Miyazaki-Okinawa Cable (MOC)

Overview

The Miyazaki-Okinawa Cable (MOC) is a domestic submarine cable system operating entirely within Japan. It connects the city of Miyazaki, on the island of Kyushu, with Naha, the principal city of Okinawa Prefecture. The cable serves the intra-Japan corridor linking the Japanese mainland with the Ryukyu island chain.

Route and Landings

Both landing points are located in Japan. The cable lands at Miyazaki, situated on the southeastern coast of Kyushu, and at Naha, on the main island of Okinawa. These are the only two landing points on the system.

Ownership and Operators

The Miyazaki-Okinawa Cable is owned and operated by KDDI Corporation, one of Japan's principal telecommunications carriers. As the sole owner, KDDI manages the system without a consortium structure.

Status and Timeline

The cable entered service in 1997 and has now been operational for approximately 29 years. It was among the earlier submarine cable systems to serve Japan's domestic connectivity needs, with Japan's submarine cable network as a whole beginning to develop from 1996 onward.

Regional Context

Within Japan's broader submarine cable landscape, the Miyazaki-Okinawa Cable is a compact domestic system. Japan hosts 38 submarine cables across 46 landing points, with an average cable length of around 6,374 km — reflecting the country's heavy participation in long-haul international routes. The MOC stands apart from this pattern, functioning as a shorter intra-national link rather than a transoceanic system. Regional cables with landing points in Japan include large international systems such as EAC-C2C (RFS 2002), APCN-2 (RFS 2001), the Trans-Pacific Express Cable System (RFS 2008), JUPITER (RFS 2020), the New Cross Pacific Cable System (RFS 2018), and the Australia-Japan Cable (RFS 2001) — all of which operate on a substantially different scale and scope from the MOC.

Strategic Role

The Miyazaki-Okinawa Cable provides a dedicated submarine connection between Japan's Kyushu region and Okinawa Prefecture. By linking these two geographically separated parts of Japan, it supports terrestrial and communications continuity between the mainland and the Ryukyu Islands, a chain that would otherwise depend on longer routing paths through international or indirect cable systems. The cable represents KDDI's provision of direct domestic submarine infrastructure for this specific corridor.