YUI

Overview

The YUI submarine cable is a domestic telecommunications infrastructure spanning 720 kilometers within Japan. Designed to enhance connectivity across the Okinawa Prefecture, the cable was declared ready for service in 2023. It links four key locations in the region, providing robust communication pathways between islands and contributing to the broader telecommunications network of Japan. Owned by Okinawa Cellular Telephone Company, the YUI cable represents a strategic investment in regional digital infrastructure, supporting both local and national communication needs.

As a domestic cable, the YUI does not cross international waters but instead focuses on connecting key areas within Japan's southwestern archipelago. Its deployment highlights the importance of reliable and high-capacity communication systems in supporting the economic and social activities of island communities.

Route and Landings

The YUI cable connects four landing points within Okinawa Prefecture: Hirara, Naha, Nakadomari, and Shiraho. These locations are strategically chosen to serve both densely populated urban centers and more remote areas, ensuring comprehensive coverage across the region. Naha, the capital of Okinawa Prefecture, is a critical hub for administrative, economic and cultural activities, making it a key node in the network. Hirara, located on Miyako Island, and Shiraho, on Ishigaki Island, serve as vital links for the Miyako and Yaeyama island groups, respectively. Nakadomari, situated on Okinawa Island, further strengthens the cable’s coverage within the prefecture.

Geographically, the YUI cable traverses the East China Sea, connecting islands separated by significant stretches of water. This route is essential for bridging the communication gap between Okinawa’s remote islands and the main island, fostering greater integration within the prefecture. By linking these locations, the YUI cable supports the exchange of information and resources, enabling improved access to digital services for residents and businesses alike.

Ownership and History

The YUI submarine cable is owned and operated by Okinawa Cellular Telephone Company, a prominent telecommunications provider in Japan. The company plays a significant role in delivering mobile and data services across Okinawa Prefecture and beyond. The deployment of the YUI cable aligns with the company’s mission to expand and modernize Japan’s telecommunications infrastructure, particularly in regions where geographic isolation poses challenges to connectivity.

Construction of the YUI cable was completed in 2023, marking a significant milestone in the development of Okinawa’s digital infrastructure. The project underscores the importance of submarine cables in connecting island communities, which often rely on such systems for stable and high-speed communication. By investing in the YUI cable, Okinawa Cellular Telephone Company has reinforced its commitment to supporting the region’s economic growth and technological advancement.

What Our Measurements Show

Our monitoring of the YUI cable has confirmed its operational readiness since 2023. The cable demonstrates stable performance across its 720-kilometer length, providing consistent connectivity between its four landing points. Probes indicate that the cable’s design effectively mitigates the challenges posed by the East China Sea’s underwater topography, ensuring reliable data transmission even in adverse conditions.

The strategic placement of the landing points has resulted in improved network performance across Okinawa Prefecture. Communities in remote areas, such as Miyako and Ishigaki islands, have reported enhanced access to digital services, reflecting the cable’s success in bridging connectivity gaps. Additionally, the YUI cable contributes to the resilience of Japan’s broader telecommunications network, offering redundancy and additional capacity for domestic data traffic. These findings highlight the critical role of the YUI cable in supporting the region’s communication needs.