SEA-US

SEA-US: A Trans-Pacific Submarine Cable Linking Southeast Asia and the United States

The SEA-US submarine cable system spans approximately 14,500 kilometers, connecting Southeast Asia, Micronesia, and the United States. It is owned by a consortium of operators including GTA TeleGuam, Globe Telecom, Hawaiian Telcom, Lightstorm Telecom, and Telin. SEA-US was recorded as ready for service (RFS) in 2017 in the GeoCables database, and it is currently listed as in service. The cable's landing points include Davao in the Philippines, Hermosa Beach in the United States, Kauditan in Indonesia, Magachgil in Micronesia, Makaha in the United States, Ngeremlengui in Palau, and Piti in Guam. What makes SEA-US particularly interesting is its route, which bypasses the crowded and earthquake-prone Luzon Strait near Taiwan, a common bottleneck for trans-Pacific cables. This strategic design enhances the cable's resilience against natural disasters. However, several technical details about SEA-US remain undisclosed, including its design capacity, the number of fiber pairs, and the supplier or technology used in its construction.

Quick facts

Length	14,500 km
Ready for Service (RFS)	2017 (GeoCables database; conflicting industry sources not surfaced)
Owners	GTA TeleGuam, Globe Telecom, Hawaiian Telcom, Lightstorm Telecom, Telin
Status	In service
Design Capacity	Not disclosed
Fiber Pairs	Not disclosed
Supplier	Not disclosed
Technology	Not disclosed
Landing Points	Davao (Philippines), Hermosa Beach (United States), Kauditan (Indonesia), Magachgil (Micronesia), Makaha (United States), Ngeremlengui (Palau), Piti (Guam)

Show SEA-US on the interactive cable map

Route

SEA-US connects seven landing points across four countries: the United States, the Philippines, Indonesia, and Palau, with additional connections to Micronesia and Guam. The cable lands at Hermosa Beach and Makaha in the United States, providing connectivity to the mainland and Hawaii. In Southeast Asia, it lands at Davao in the Philippines and Kauditan in Indonesia. The cable also serves smaller island nations, landing at Magachgil in Micronesia and Ngeremlengui in Palau, as well as Piti in Guam. This diverse route avoids the Luzon Strait, which is prone to seismic activity, offering a more stable alternative for trans-Pacific connectivity.

Why it was built and what it carries

SEA-US was designed to meet growing demand for bandwidth between Southeast Asia and the United States, driven by the proliferation of cloud computing, video streaming, and other data-intensive applications. By bypassing the Luzon Strait, the cable provides a more reliable route for international data traffic. While specific details about its design capacity and technology are not publicly disclosed, it is likely that SEA-US supports high-capacity data transmission typical of modern submarine cable systems.

History: what can be established

The GeoCables database records SEA-US as ready for service in 2017, and it has been listed as in service since then. No conflicting industry sources suggesting a different RFS year have been surfaced. The cable was developed by a consortium of operators from the United States, Southeast Asia, and Micronesia, reflecting its multinational scope.

Capacity and technology

Publicly available sources do not disclose SEA-US's design capacity, the number of fiber pairs, or the technology used in its construction. Without operator documentation, attributing these specifications would be speculative. However, given its trans-Pacific scope, SEA-US is likely equipped with advanced optical technologies capable of supporting high-capacity data transmission.

Latency: the physics

The computed one-way light propagation latency for SEA-US over its 14,500-kilometer wet segment is approximately 71.1 milliseconds, resulting in a theoretical round-trip time (RTT) floor of 142.2 milliseconds. Real-world latency measurements are higher due to land tails, terminal equipment, and routing. Live measurements from remote probes show min/avg RTTs such as Hermosa Beach -> Kauditan (118.6 ms min, 162.0 ms avg) and Sydney -> Kauditan (107.2 ms min, 108.0 ms avg). However, some of these reported minimums are below the physical floor of 142.2 ms, indicating measurement artifacts such as rate-limited ICMP replies from intermediate routers. These artifacts should not be interpreted as the cable's actual latency performance.

Redundancy: what happens if it breaks

If SEA-US experiences a fault, redundancy is available through other cables landing at its key points. For example, Davao is connected by Apricot, Asia Connect Cable-1 (ACC-1), and Bifrost, while Hermosa Beach has connections to Asia Connect Cable-1 (ACC-1), JUPITER, ORCA, and Southern Cross NEXT. Piti in Guam is particularly well-served, with alternatives such as Atisa, Bulikula, Echo, HANTRU1 Cable System, Japan-Guam-Australia North (JGA-N), Japan-Guam-Australia South (JGA-S), PIPE Pacific Cable-1 (PPC-1), and Tata TGN-Pacific. These alternative routes help ensure continuity of service in the event of a cable fault.

Bottom line

• SEA-US spans 14,500 kilometers, connecting Southeast Asia, Micronesia, and the United States.
• Its route avoids the earthquake-prone Luzon Strait, enhancing resilience.
• Key landing points include Davao, Hermosa Beach, Kauditan, Magachgil, Makaha, Ngeremlengui, and Piti.
• Design capacity, fiber pairs, supplier, and technology are not publicly disclosed.
• Theoretical RTT floor is 142.2 ms; live measurements show artifacts below this value.
• Redundancy is available through multiple alternative cables at key landing points.