SEALink: A regional submarine cable connecting Southeast Alaska
SEALink is a submarine telecommunications cable system operated by Alaska Power & Telephone Company Wireless (APTW). It spans 345 km, linking three landing points in Southeast Alaska:
Coffman Cove,
Lena Point, and
Petersburg. As of 2023, GeoCables data lists the cable as in service, though its design capacity, fiber pair count, supplier, and technology specifics are not publicly disclosed.
What makes SEALink notable is its role in connecting relatively remote communities in Alaska to broader digital infrastructure. The cable intersects with other systems at its landing points, including
SEALink South at Coffman Cove,
Lynn Canal Fiber and
NorthStar at Lena Point, and
Alaska United Southeast (AU-SE) at Petersburg. This interconnection provides redundancy and enhances regional connectivity, though public information on SEALink's individual performance metrics and technical specifications remains scarce.
Quick facts
| Cable name | SEALink |
| Length | 345 km |
| Ready for service (RFS) | 2023 (GeoCables database) |
| Owners | Alaska Power & Telephone Company Wireless (APTW) |
| Status | In service |
| Design capacity | Not disclosed |
| Fiber pairs | Not disclosed |
| Supplier | Not disclosed |
| Technology | Not disclosed |
| Landing points | Coffman Cove (United States); Lena Point (United States); Petersburg (United States) |
Route
SEALink connects three communities in Southeast Alaska: Coffman Cove on Prince of Wales Island, Lena Point near Juneau, and Petersburg on Mitkof Island. These locations are geographically dispersed across the region, reflecting the cable's purpose of improving connectivity in areas where terrestrial infrastructure is limited or impractical due to rugged terrain and maritime geography. The cable's route traverses underwater channels and fjords characteristic of Southeast Alaska, a region known for its complex coastal geography.
Why it was built and what it carries
The SEALink cable was built to enhance telecommunications infrastructure in Southeast Alaska, a region where reliable internet access is often challenged by geographic isolation. By connecting Coffman Cove, Lena Point, and Petersburg, SEALink enables faster and more reliable data transmission for residents, businesses, and public services in these communities. While the specific types of traffic carried by SEALink are not disclosed, submarine cables typically support internet, voice, and data services. SEALink also plays a role in regional redundancy by interconnecting with other cable systems at its landing points.
History: what can be established
GeoCables records SEALink as ready for service in 2023, and it is currently listed as operational. No conflicting dates have been identified in publicly available industry sources, though it is worth noting that submarine cable projects often face delays due to permitting, environmental surveys, and logistical challenges. Without operator documentation, it is not possible to confirm whether SEALink experienced such delays or whether its deployment proceeded as planned.
Capacity and technology
The design capacity, fiber pair count, and technology specifics of SEALink have not been disclosed publicly. This lack of information is not unusual for smaller regional cable systems, which may not release detailed specifications unless required for regulatory or marketing purposes. Without this data, it cannot be stated whether SEALink employs advanced technologies such as wavelength division multiplexing (WDM) or whether it is optimized for high-capacity data transmission. Any assumptions about its capabilities would be speculative without operator confirmation.
Latency: the physics
Based on the cable's length of 345 km, the theoretical one-way light propagation time through the fiber is approximately 1.7 milliseconds. This results in a round-trip time (RTT) floor of 3.4 milliseconds for the wet segment alone, assuming light travels at 200,000 to 204,000 km/s in fiber. However, real-world latency is higher due to additional factors such as land tail connections, terminal equipment processing, and routing inefficiencies. Currently, no live latency measurements for SEALink are available, and any estimates beyond the theoretical floor would require direct testing.
Redundancy: what happens if it breaks
SEALink's landing points are interconnected with other submarine cable systems, providing some degree of redundancy. At Coffman Cove, SEALink South offers an alternative route; Lena Point connects to Lynn Canal Fiber and NorthStar; and Petersburg links to Alaska United Southeast (AU-SE). In the event of a SEALink outage, traffic could potentially be rerouted through these systems, though the extent of redundancy depends on network configurations and capacity constraints. Repairs to submarine cables typically involve specialized vessels and equipment, and the timeline for restoration depends on factors such as weather conditions and the nature of the fault.
Bottom line
- SEALink is a 345 km submarine cable connecting Coffman Cove, Lena Point, and Petersburg in Southeast Alaska.
- Owned by Alaska Power & Telephone Company Wireless (APTW), it was recorded as ready for service in 2023.
- Its design capacity, fiber pair count, supplier, and technology specifics are not publicly disclosed.
- Theoretical latency for the wet segment is approximately 3.4 ms RTT, though real-world latency is higher.
- Interconnections with other cable systems at its landing points provide regional redundancy.