Tasman Global Access (TGA) Cable: A Trans-Tasman Submarine Link
The Tasman Global Access (TGA) Cable is a submarine telecommunications cable connecting Australia and New Zealand across the Tasman Sea. Spanning 2,288 kilometers, it links
Oxford Falls in Australia with
Raglan in New Zealand and is operated by a consortium comprising One NZ, Spark New Zealand, and Telstra. The cable was recorded as ready for service in 2017 according to GeoCables data, though discrepancies in the industry regarding its exact commissioning date are noted below.
What makes the TGA Cable particularly significant is its role in enhancing connectivity between Australia and New Zealand, providing additional capacity and redundancy for data traffic in the region. However, several technical specifications, including its design capacity, fiber pair count, and supplier, remain undisclosed in publicly available sources. This lack of transparency limits a full understanding of its technological capabilities.
Quick facts
| Length | 2,288 km |
| Ready for Service (RFS) | 2017 (GeoCables database; industry discrepancies noted) |
| Owners | One NZ, Spark New Zealand, Telstra |
| Status | In service |
| Design Capacity | Not disclosed |
| Fiber Pairs | Not disclosed |
| Supplier | Not disclosed |
| Technology | Not disclosed |
| Landing Points | Oxford Falls (Australia); Raglan (New Zealand) |
🗺 Show Tasman Global Access (TGA) Cable on the interactive cable map
Route
The TGA Cable connects Oxford Falls in Sydney, Australia, to Raglan, a coastal town on New Zealand's North Island. Oxford Falls is a notable hub for international cable landings, also hosting the
Australia-Japan Cable (AJC). Raglan, while smaller in scale, is an important landing site that also serves the
Aqualink cable. The corridor crosses the Tasman Sea, a challenging marine environment known for its variable weather and deep waters.
Why it was built and what it carries
The TGA Cable was built to improve trans-Tasman connectivity, offering enhanced bandwidth and redundancy for telecommunications between Australia and New Zealand. It serves as an alternative to existing cables, such as the Southern Cross Cable Network, which also links the two countries. By diversifying routes, the TGA Cable reduces the risk of service disruptions caused by cable faults or maintenance on other systems. It carries internet traffic, data services, and potentially enterprise communications, although specific traffic types are not disclosed.
History: what can be established
GeoCables data records the TGA Cable as ready for service in 2017. However, some industry sources suggest alternative commissioning dates, possibly due to delays in final testing or phased activation of the cable. Such discrepancies are not uncommon in the submarine cable industry, where project timelines can be influenced by environmental challenges, regulatory approvals, or technical issues. Without official documentation from the operators, the exact timeline cannot be definitively confirmed.
Capacity and technology
Publicly available information does not disclose the TGA Cable's design capacity, fiber pair count, or supplier. While modern submarine cables typically offer terabit-scale capacities and employ advanced technologies such as coherent optical transmission, attributing these features to the TGA Cable without operator confirmation would be speculative. The cable's redundancy role suggests it was designed to complement existing systems rather than serve as a primary framework for trans-Tasman traffic.
Latency: the physics
Theoretical calculations based on the cable's length of 2,288 km yield a one-way light propagation time of approximately 11.2 milliseconds, with a round-trip time (RTT) floor of 22.4 milliseconds for the wet segment. However, real-world latency measurements are higher due to additional factors such as land-based transmission, terminal equipment, and routing. GeoCables live probes recorded minimum RTTs of 25.9 milliseconds between Oxford Falls and Raglan, and 27.3 milliseconds between Sydney and Raglan. These figures align with expectations for a cable of this length, considering the added latency from land tails and network overhead.
Redundancy: what happens if it breaks
In the event of a fault or outage on the TGA Cable, alternative routes exist for trans-Tasman connectivity. Oxford Falls hosts the Australia-Japan Cable (AJC), while Raglan is a landing point for the Aqualink cable. Additionally, the Southern Cross Cable Network provides another major connection between Australia and New Zealand. Repairing a submarine cable typically involves deploying specialized cable ships equipped with remotely operated vehicles (ROVs) to locate and fix the fault. Repairs can be delayed by adverse weather conditions in the Tasman Sea, but redundancy mitigates the impact on regional connectivity.
Bottom line
- The TGA Cable spans 2,288 km, connecting Oxford Falls (Australia) to Raglan (New Zealand).
- Recorded as ready for service in 2017, though discrepancies in industry sources exist.
- Owned by One NZ, Spark New Zealand, and Telstra.
- Key technical details, such as design capacity and fiber pairs, remain undisclosed.
- Theoretical latency floor is 22.4 ms RTT over the wet segment, with real-world RTT measurements slightly higher.
- Redundancy is provided by other cables in the corridor, including the Southern Cross Cable Network.