Rebun, Japan

Rebun: Submarine Cable Landing Point

Rebun is an island located in the Sea of Japan off the northwestern tip of Hokkaido, Japan. Stretching approximately 29 kilometres from north to south and 8 kilometres from east to west, the island covers around 80 square kilometres and sits roughly 50 kilometres off the Hokkaido coast. As an island community separated from the Japanese mainland by open water, Rebun depends on submarine cable infrastructure to maintain connectivity with the broader national network.

One submarine cable lands at Rebun, connecting the island to other points within Japan. The Hokkaido-Rebun-Rishiri cable links Rebun with its immediate geographic neighbours — Hokkaido and Rishiri Island — forming a short intra-national corridor that serves the island cluster situated at the northwestern edge of the Japanese archipelago.

Cables Landing at Rebun

The Hokkaido-Rebun-Rishiri cable is the sole submarine cable landing at Rebun. At 64 kilometres in length, it is a compact domestic cable with a Ready for Service (RFS) year of 2011, noted as a draft designation. As its name indicates, the cable connects Hokkaido, Rebun, and Rishiri — all within Japan — forming a short triangular route that links the two outlying islands of Rebun and Rishiri to the main island of Hokkaido. Rishiri Island lies approximately 10 kilometres southeast of Rebun, separated from it by the Rebun Channel, making this cable a logical piece of infrastructure for the immediate island group.

Regional Context

Within Japan's submarine cable network, which spans 51 cables across 68 landing points, Rebun hosts a single cable and ranks in the top 68 percent of Japanese landing points by cable count. Landing points such as Shima (12 cables), Maruyama (9 cables), and Chikura (8 cables) serve as the country's most heavily connected nodes, handling large volumes of international and domestic traffic, while Rebun occupies a more specialised role as a single-cable island terminus serving a localised intra-island corridor in the Sea of Japan.

Network Role

Rebun functions as a single-cable terminus rather than a multi-cable hub. Its one connection, the Hokkaido-Rebun-Rishiri cable, establishes a domestic link between Rebun Island, Rishiri Island, and Hokkaido, enabling the island community to participate in Japan's national telecommunications network. The cable's short span of 64 kilometres reflects the geographically compact nature of this island cluster rather than any intercontinental or long-haul routing function.

Within the broader submarine cable graph of Japan, Rebun represents the kind of localised, intra-national landing point that addresses island connectivity at the periphery of the archipelago. The presence of such infrastructure at a remote island in the Sea of Japan demonstrates how Japan's network of 68 landing points extends well beyond major international exchange hubs to reach isolated communities at the country's geographic extremities.