Kitadaito Island: Connecting Okinawa's Remote Communities
The Kitadaito Island submarine cable is a repeatered optical fiber system linking Kitadaito, a remote island in Japan's Okinawa Prefecture, to
Yaese on Okinawa's main island. This 410-kilometer cable, owned by Okinawa Prefecture, is listed as in service as of 2022 according to GeoCables data. It employs optical wavelength division multiplexing (WDM) technology, a standard approach for maximizing data transmission capacity over long distances. The cable was supplied by NEC and OCC Corporation, both prominent players in the submarine cable industry.
What stands out about this cable is its role in providing connectivity to Kitadaito, a geographically isolated island with limited infrastructure. While the design capacity and number of fiber pairs are not publicly disclosed, its deployment reflects the growing need for reliable telecommunications links to support the island's residents and economic activities. Uncertainty remains about certain technical specifics, and no live latency measurements are available to corroborate theoretical calculations.
Quick facts
| Name | Kitadaito Island |
| Length | 410 km |
| Ready-for-service year | 2022 (GeoCables database) |
| Owner | Okinawa Prefecture |
| Status | In service |
| Design capacity | Not disclosed |
| Fiber pairs | Not disclosed |
| Supplier | NEC / OCC Corporation |
| Technology | Optical WDM, Repeatered |
| Landing points | Kitadaito (Japan); Yaese (Japan) |
| Other cables at Kitadaito | Daito Loop |
| Other cables at Yaese | Okinawa-Miyakojima-Ishigaki |
Route
The cable connects Kitadaito, a small island located east of Okinawa's main island, to Yaese, a town on the southern part of Okinawa's main island. Kitadaito is part of the Daito Islands group, which is known for its remote location and limited accessibility. The cable's route spans 410 kilometers beneath the East China Sea, traversing a region characterized by deep waters and occasional seismic activity. The landing stations at Kitadaito and Yaese are critical nodes for integrating the island into Okinawa's broader telecommunications network.
Why it was built and what it carries
The Kitadaito Island cable was built to address the connectivity needs of Kitadaito, which, like many remote islands, faces challenges in accessing reliable telecommunications infrastructure. By linking Kitadaito to Yaese, the cable enables internet access, phone services, and data transmission for residents, businesses, and public services on the island. Its construction aligns with broader efforts by Okinawa Prefecture to improve digital inclusion and support economic development in remote communities.
Given the lack of publicly disclosed data on design capacity and fiber pairs, it is unclear how much traffic the cable can handle. However, its use of optical WDM technology suggests it is designed to accommodate significant bandwidth demands.
History: what can be established
GeoCables records the cable's ready-for-service year as 2022, and it is currently listed as in service. No conflicting dates have surfaced from industry sources, making 2022 the most likely commissioning year. The suppliers, NEC and OCC Corporation, are well-known for their expertise in submarine cable systems, and their involvement underscores the cable's adherence to industry standards.
Capacity and technology
The Kitadaito Island cable employs optical WDM technology with repeaters to amplify signals over its 410-kilometer length. While this technology is standard for modern submarine cables, the design capacity and number of fiber pairs are not publicly disclosed. Without operator documentation, attributing specific values would be speculative.
Latency: the physics
Theoretical one-way light propagation over the 410 km wet segment is approximately 2.0 milliseconds, resulting in a round-trip time (RTT) floor of 4.0 milliseconds. However, real-world latency is higher due to additional factors such as signal processing delays in terminal equipment, routing inefficiencies, and land-based network segments. As no live latency measurements are available for this cable, the theoretical values remain the best estimate.
Redundancy: what happens if it breaks
In the event of a fault or breakage, redundancy for Kitadaito Island's connectivity would likely rely on alternative cables or satellite links. Kitadaito is also served by the Daito Loop cable, which may provide some level of backup. At Yaese, the Okinawa-Miyakojima-Ishigaki cable offers another potential alternative for rerouting traffic. Repairs to submarine cables typically involve deploying specialized cable ships equipped with remotely operated vehicles (ROVs) to locate and fix the damaged segment. Given the cable's location in a seismically active region, repair logistics may be complicated by challenging underwater terrain.
Bottom line
- The Kitadaito Island cable spans 410 km and connects Kitadaito to Yaese in Okinawa Prefecture.
- It was recorded as ready for service in 2022, with no conflicting dates from other sources.
- Owned by Okinawa Prefecture, the cable uses optical WDM technology and repeaters.
- Design capacity and fiber pair count are not publicly disclosed.
- Latency is theoretically 4.0 ms RTT over the wet segment, though real-world values are higher.
- Redundancy options include the Daito Loop cable and Okinawa-Miyakojima-Ishigaki cable.