Mikurashima, Japan

Mikurashima: A Remote Link in Japan's Submarine Cable Network

Mikurashima, a volcanic island in the Pacific Ocean, is one of the Izu Seven Islands and lies approximately 200 kilometers south of Tokyo. Despite its small size and remote location, this island plays a modest yet important role in Japan's submarine cable infrastructure, hosting the "5 Villages 6 Islands" cable. This cable connects Mikurashima to eight other landing points in the Izu archipelago, stitching together a chain of islands that rely on shared connectivity for communication and services.

The "5 Villages 6 Islands" Cable

The "5 Villages 6 Islands" cable, which became operational in 2019, spans 355 kilometers and exclusively serves domestic points within Japan. Mikurashima is one of nine landing points on this cable, alongside neighbors such as Miyake, Hachijo, and Kozushima. Unlike major landing points like Shima or Maruyama, which host multiple international cables, Mikurashima is part of a regional network designed to connect smaller, isolated communities. This cable does not provide direct international connectivity but instead links Mikurashima to broader national networks through its chain of island connections.

Connectivity in a Remote Setting

Mikurashima's geographic isolation makes its submarine cable connection essential for maintaining communication with the outside world. The island's population, recorded as 351 in 2009, depends on this infrastructure for internet access, phone services, and digital communication. The cable ensures that Mikurashima remains connected to mainland Japan, despite its volcanic terrain and remote location within the Fuji-Hakone-Izu National Park.

Latency Observations

GeoCables' proprietary latency measurements reveal an average round-trip latency of 272 milliseconds from Mikurashima to nine monitored source cities, with the best observed latency at 80 milliseconds. These figures highlight the challenges of connecting a remote island to the broader network but also demonstrate the effectiveness of the "5 Villages 6 Islands" cable in providing reliable service.

Positioning Mikurashima in Japan's Cable Landscape

Japan is home to 51 submarine cables spread across 68 landing points, with an average cable length of 5696 kilometers. Mikurashima ranks in the top 68% of landing points by cable count, hosting one cable. While this pales in comparison to hubs like Shima (12 cables) or Chikura (8 cables), Mikurashima's role as part of a regional chain is significant for the Izu Islands. The cable here is not about high-capacity international traffic but about ensuring that smaller communities remain connected.

A Chain of Islands, A Shared Connection

The "5 Villages 6 Islands" cable exemplifies how submarine cables can serve not just major urban centers but also remote, sparsely populated regions. For Mikurashima, this single cable is a lifeline to the rest of Japan, ensuring that even the most isolated corners of the country are part of the digital age.