IRIS: Iceland-Ireland submarine cable
The IRIS cable is a submarine telecommunications system connecting Iceland and Ireland, with landing points in
Thorlakshofn, Iceland, and
Galway, Ireland. Spanning approximately 1770 kilometers, it is owned by Farice, an Icelandic operator specializing in international connectivity. IRIS is listed as in service, with its ready-for-service (RFS) year recorded as 2023 in the GeoCables database.
What makes IRIS notable is its role in strengthening Iceland's international connectivity, providing an alternative route to existing cables and enhancing redundancy. However, several technical details about the cable, including its design capacity, fiber pair count, and supplier, have not been disclosed in publicly available sources. This absence of information leaves certain aspects of the cable's capabilities open to speculation.
Quick facts
| Name | IRIS |
| Length | 1770 km |
| Ready-for-Service Year | 2023 (GeoCables database) |
| Owners | Farice |
| Status | In service |
| Design Capacity | Not disclosed |
| Fiber Pairs | Not disclosed |
| Supplier | Not disclosed |
| Landing Points | Galway (Ireland), Thorlakshofn (Iceland) |
Route
The IRIS cable connects Galway on the west coast of Ireland to Thorlakshofn on the southern coast of Iceland. This route spans the North Atlantic Ocean, a corridor that is critical for linking Iceland to mainland Europe and beyond. Galway serves as a key telecommunications hub in Ireland, while Thorlakshofn is strategically positioned to provide connectivity for Iceland. The cable's route avoids more congested submarine cable corridors, offering improved resilience for Iceland's international communications.
Why it was built and what it carries
IRIS was built to enhance Iceland's international connectivity and provide redundancy to existing cables. Iceland is geographically isolated, making reliable submarine cable connections essential for its economy, which relies heavily on digital services, data centers, and renewable energy exports. By connecting directly to Ireland, IRIS offers an alternative route to Europe, complementing Farice's other cables, FARICE-1 and DANICE.
While the specific data traffic carried by IRIS has not been disclosed, it is likely to include internet, cloud services, and enterprise data, supporting Iceland's growing technology and data center industries.
History: what can be established
The GeoCables database records IRIS as ready for service in 2023. Publicly available sources corroborate this timeline, though some industry reports occasionally list submarine cable RFS dates differently due to delays or phased activations. If any conflicting dates exist, they are not currently documented for IRIS.
Farice, the cable's owner, has a history of operating submarine cables that connect Iceland to Europe, and IRIS represents an expansion of its network. The cable's construction reflects Iceland's strategic focus on improving digital infrastructure and ensuring strong international connectivity.
Capacity and technology
Details about IRIS's design capacity, fiber pair count, and supplier have not been disclosed in publicly available sources. Without operator documentation, attributing specific technological features would be speculative. However, modern submarine cables typically employ dense wavelength division multiplexing (DWDM) technology, enabling high-capacity data transmission. The absence of disclosed specifications makes it difficult to assess IRIS's exact capabilities compared to other cables in the region.
Latency: the physics
The computed one-way light propagation latency for IRIS over its 1770 km length is approximately 8.7 milliseconds, with a theoretical round-trip time (RTT) floor of 17.4 milliseconds. This calculation assumes light traveling through fiber at speeds between 200,000 and 204,000 km/s. Real-world latency, however, is higher due to additional factors such as signal processing, routing, and the land-based network segments at both ends.
GeoCables' live measurements of the full internet path between Galway and Thorlakshofn show an average RTT of 39.6 milliseconds in one direction and 73.2 milliseconds in the other. These figures include latency contributions from routers, switches, and terrestrial links, which are not part of the submarine cable itself. A reported minimum RTT of 1.6 milliseconds is below the physical floor and is clearly a measurement artifact caused by rate-limited ICMP replies from intermediate network devices. Such values should not be interpreted as the cable's actual performance.
Redundancy: what happens if it breaks
If IRIS were to experience a fault, Iceland would rely on alternative submarine cables for connectivity. Farice operates two other cables, FARICE-1 and DANICE, which link Iceland to Scotland and Denmark, respectively. These cables provide redundancy and ensure that Iceland remains connected to Europe even in the event of a disruption to IRIS. Repairing submarine cables typically involves deploying specialized cable ships to locate, retrieve, and repair the damaged section, a process that can take days to weeks depending on weather and logistical factors.
Bottom line
- IRIS is a submarine cable connecting Iceland and Ireland, spanning 1770 km.
- Owned by Farice, it is listed as in service with an RFS year of 2023.
- Technical details such as design capacity, fiber pairs, and supplier are not publicly disclosed.
- Theoretical one-way latency is 8.7 ms; real-world RTT measurements are higher due to land-based network factors.
- Redundancy is provided by FARICE-1 and DANICE, ensuring Iceland's connectivity in case of faults.