Submarine cables in New Zealand
Geographically isolated New Zealand depends on a network of submarine cables to connect with the rest of the world. Around 99 percent of international data traffic enters and leaves the country through these subsea links.
They carry everything: voice, internet and cloud traffic, underpinning business, finance and everyday communications.
International connectivity
Trans-Tasman cables link New Zealand to Australia. From there, traffic can travel on to South-East Asia and beyond. Trans-Pacific cables connect New Zealand to Hawaii and the west coast of the United States. Some also link to Pacific Island nations.
Distance matters. Data travelling between New Zealand and overseas destinations takes longer than traffic moving within larger, more densely connected regions. Modern fibre cables minimise this delay, but latency is still noticeable for some applications such as real-time communications and online gaming.
Performance depends on both capacity and routing. Direct routes are faster. When there is ample capacity, international connections feel fast and responsive. Congestion or faults can slow speeds, particularly at peak times.
Submarine cables have a direct economic impact. They enable cloud computing, support international trade, and allow New Zealand businesses to operate globally. Media streaming, financial transactions and everyday online services all depend on reliable international links.
There are no practical alternatives to submarine cables. While satellite communications can carry international traffic they only offer a fraction of the capacity of fibre and typically have higher latency.
Key submarine cables serving New Zealand
New Zealand’s international connectivity relies on a small number of major cable systems.
Southern Cross Cable Network
The Southern Cross Cable Network has long been the backbone of New Zealand’s international connectivity. It links Auckland to Australia, Hawaii and the United States using multiple paths for resilience. The Southern Cross Next cable reaches New Zealand via a branching unit from its main Sydney to Los Angeles cable.
Hawaiki Cable
The Hawaiki Cable provides an alternative route between New Zealand, Australia, Hawaii and the US west coast. It increased competition and added capacity when it entered service.
Hawaiki Nui (proposed/expansion)
An extension of the Hawaiki system aims to expand connectivity further across the Pacific, improving redundancy and linking additional destinations. It will also offer routes to Singapore and Indonesia.
Tasman Global Access
Tasman Global Access offers a direct route between New Zealand and New South Wales on the East coast of Australia.
Tasman Ring
The planned Tasman Ring cable aims to link Auckland, New Plymouth, Greymouth and Invercargill in New Zealand with Sydney and Melbourne in Australia. It is being built by the owners of a hyperscale data centre planned for Makarewa in Southland, highlighting the growing link between submarine cables and large-scale data centre investment.
How submarine cables connect within New Zealand
International cables come ashore at landing stations, mainly in the North Island. From there, traffic is carried across the country on domestic fibre networks to reach businesses, homes and data centres.
Submarine cables are only one part of the system. Their value depends on how well they integrate with national infrastructure, including long-distance fibre links and local access networks.
Resilience and risk
Submarine cables are robust but not immune to damage. Earthquakes, volcanoes, fishing activity and ship anchors can all cause faults.
New Zealand’s reliance on a limited number of international cables creates some vulnerability. However, multiple cable systems and diverse routes help provide redundancy. When one cable fails, traffic can usually be rerouted, although users may notice slower speeds.
Submarine cables are considered strategic infrastructure and are potential targets for espionage or hostile action.
Submarine cables and satellites
Submarine cables and satellite communications serve different roles.
Cables offer:
• Very high capacity
• Lower latency
• Lower cost per unit of data
Satellites offer:
• Coverage in remote areas
• An alternative path when cables are unavailable
In practice, cables carry the vast majority of New Zealand’s international traffic, while satellites play a complementary role.
The future of submarine connectivity
Demand for international bandwidth continues to grow as cloud services, streaming media and data-intensive applications become more common.
New cable projects and upgrades are likely to focus on increasing capacity, improving resilience and strengthening links with Asia-Pacific markets. Submarine infrastructure is also becoming more strategically important as governments and businesses place greater emphasis on security and reliability.
Further reading on submarine cables
This page is part of a series of background briefings on New Zealand’s telecommunications industry: