Southern Cross NEXT

Southern Cross NEXT: A Trans-Pacific Submarine Cable

Southern Cross NEXT is a submarine telecommunications cable connecting multiple locations across the Pacific Ocean. It spans approximately 13,700 kilometers, linking Australia, New Zealand, the United States, and several Pacific island nations. Owned by Southern Cross Cable Network, the cable is listed as in service and was recorded as ready-for-service in 2022 according to GeoCables data. However, the design capacity, fiber pair count, supplier, and technology details have not been disclosed publicly, leaving these aspects uncertain. What makes Southern Cross NEXT particularly interesting is its role in enhancing connectivity across the Pacific region, a corridor with significant demand for data traffic. The cable complements existing infrastructure while providing redundancy for other cables in the area. Despite its importance, many technical details remain unavailable, highlighting the opacity often associated with submarine cable projects.

Quick facts

Name	Southern Cross NEXT
Length	13,700 km
Ready-for-Service Year	2022 (GeoCables database)
Owner	Southern Cross Cable Network
Status	In service
Design Capacity	Not disclosed
Fiber Pairs	Not disclosed
Supplier	Not disclosed
Technology	Not disclosed
Landing Points	Alexandria (Australia), Hermosa Beach (United States), Nukunonu (Tokelau), Savusavu (Fiji), Suva (Fiji), Tabwakea (Kiribati), Takapuna (New Zealand)

Route

Southern Cross NEXT connects seven landing points across the Pacific Ocean. In Australia, the cable lands at Alexandria, which also hosts INDIGO-Central and the Southern Cross Cable Network (SCCN). In the United States, Hermosa Beach serves as the landing site, sharing space with cables such as Asia Connect Cable-1 (ACC-1), JUPITER, ORCA, and SEA-US. In the Pacific islands, the cable lands at Nukunonu in Tokelau, Savusavu and Suva in Fiji, Tabwakea in Kiribati, and Takapuna in New Zealand. These landing points are strategically chosen to maximize connectivity and redundancy across the region.

Why it was built and what it carries

Southern Cross NEXT was built to address the growing demand for data traffic in the Pacific region. It serves as a complementary system to the existing Southern Cross Cable Network, offering additional capacity and redundancy. The cable supports telecommunications, internet services, and data transfer for businesses and consumers in the connected countries. Given the lack of public disclosure on its design capacity, its exact data-carrying capabilities remain unclear.

History: what can be established

Southern Cross NEXT was recorded as ready-for-service in 2022 in the GeoCables database. While this date is consistent with the cable's operational status, industry sources occasionally report discrepancies in ready-for-service years for submarine cables. Possible explanations for such conflicts include delays in final testing, staggered activation of segments, or differences in the definition of "ready-for-service" across operators.

Capacity and technology

The design capacity and fiber pair count of Southern Cross NEXT are not publicly disclosed, nor is information about the supplier or specific technologies used. Without operator documentation, attributing these values would be speculative. Submarine cables of this scale typically employ advanced technologies such as wavelength-division multiplexing (WDM) to maximize capacity, but the exact specifications for Southern Cross NEXT remain unknown.

Latency: the physics

The computed one-way light propagation latency for Southern Cross NEXT over its 13,700 km fiber length is approximately 67.2 milliseconds, with a theoretical round-trip time (RTT) floor of 134.3 milliseconds. Real-world latency measurements are higher due to additional factors such as land-based routing, terminal equipment, and network congestion. GeoCables live measurements for the full internet path show averages such as 170.9 ms for Alexandria to Hermosa Beach and 161.3 ms for Hermosa Beach to Alexandria. However, some reported minimum values, such as 1.2 ms for Alexandria to Hermosa Beach, are below the physical latency floor and should be treated as artifacts of rate-limited ICMP replies from intermediate routers, not as actual cable performance.

Redundancy: what happens if it breaks

Southern Cross NEXT provides redundancy for other cables in the region, including the Southern Cross Cable Network (SCCN). In the event of a failure, traffic can be rerouted through alternative systems such as INDIGO-Central at Alexandria, Asia Connect Cable-1 (ACC-1) at Hermosa Beach, or Tui-Samoa at Savusavu. Repairing submarine cables typically involves deploying specialized cable ships to locate and fix the damaged section, a process that can take weeks depending on the severity of the break and weather conditions.

Bottom line

• Southern Cross NEXT spans 13,700 km and connects Australia, New Zealand, the United States, and Pacific islands.
• Recorded as ready-for-service in 2022, though industry sources sometimes report conflicting dates.
• Design capacity, fiber pair count, supplier, and technology details are not publicly disclosed.
• Computed latency floor is approximately 134.3 ms RTT, with real-world measurements showing higher values.
• Provides redundancy for other cables in the Pacific region, enhancing connectivity and reliability.