AUGUST 2025
The Strategic Future
of Subsea Cables:
Japan Case Study
By Erin Murphy and Thomas Bryja
Introduction
Given its geography as an island nation, 99 percent of Japan’s communications depend on subsea
cables. Perhaps as a natural consequence, Japan is a signicant player in the subsea cable industry, both
as a manufacturer and as a connectivity hub between North America and Asia. Japanese companies
Nippon Telegraph and Telephone (NTT) and KDDI Corporation, for example, own cable-laying
and repair ships, and the Nippon Electric Company (NEC) alone is one of the largest subsea cable
builders in the world.
Japan is home to at least 20 international submarine cable landing stations that connect to the
United States, Australia, South Korea, Southeast Asia, Russia, and the Mediterranean. These cables are
primarily located o the cities of Minamiboso in Chiba Prefecture and Shima in Mie Prefecture. Other
cables are located o the northernmost and southernmost main islands of Hokkaido and Kyushu (Figure
1). Most cable landing stations also connect to Internet exchanges in Tokyo or Osaka, where more than
80 percent of the country’s data centers are concentrated.
In 2022, then–Prime Minister Fumio Kishida recognized the vulnerabilities of Japan’s subsea internet
cables and established a $440 million fund to incentivize companies to build more stations along the
Pacic Ocean coastlines and near Tokyo. The initiative also included a push to construct data centers
in rural areas that have been impacted by demographic issues as an attempt to boost these regional
economies. In addition, Japan’s Ministry of Economy, Trade, and Industry (METI) and Ministry of
Internal Aairs and Communications (MIC) have designated the cable industry as a national security
priority and “are looking to support capital investment to boost production and installation of cables.”
