The government has announced plans to provide full-scale support for the introduction of submarine cable-laying vessels. Japanese companies own only 5 large cable-laying vessels in total, with 3 operated by NTT and 2 by KDDI, raising concerns over Japan's ability to manage risks amid growing global demand.
The government has announced plans to support the introduction of submarine cable-laying vessels. Submarine cables are a key component of global communications infrastructure, and demand is expected to grow with the spread of generative AI and cloud services. At the same time, it has been pointed out that Japanese companies own fewer cable-laying vessels than their European and US counterparts.
Submarine cables are laid on the seabed at depths of approximately 8,000 m at their deepest points. In coastal areas, their outer sheathing gives them a diameter of approximately 4-6 cm, and dozens of optical fibers are bundled inside.
As of September 2025, there were 56 large cable-laying vessels worldwide. Japanese companies owned only 5 in total, with NTT owning 3 and KDDI 2. Their service life is approximately 40 years, and some vessels are aging.
Demand for submarine cables is expected to expand further with the spread of generative AI. Many vessels are owned by overseas companies, including US companies. Japanese companies have been cited as facing constraints on orders and project timelines compared with their European and US rivals.