Australian submarine cable developer Subco said on Tuesday it will build three new subsea cable systems totalling roughly 24,000 km by 2029, targeting the bandwidth demand that AI data centres are generating across Asia-Pacific.

The largest of the three, APX East-2, is planned as a 10,000 km, 24 fibre pair system connecting Guam to Los Angeles. According to Subco, it will provide route diversity from the US to both Japan and Australia via Guam.

"This segment is vital and will serve as the backbone for trans-Pacific traffic between Asia and the US, as well as providing diverse connectivity for Australia and Japan via APX North," said Subco founder and co-CEO Bevan Slattery in a statement.

APX North, the second system, is a planned 9,500 km, 24 fibre pair cable connecting Sydney to Japan via Guam. Subco says switched branching units will allow selected fibre pairs to bypass the Guam landing station, enabling direct Japan-Australia connectivity.

The third system, APX West, is a 4,600 km, 24 fibre pair cable connecting Perth to Singapore, with branches to Jakarta and Batam. Slattery said the design allows fibre pairs to switch in and out of new regional interconnection hubs in Jakarta and Batam. Batam has become a major focus of data centre activity and subsea cable landings in Indonesia, and the cable will bring additional international bandwidth to the country.

"Singapore and Indonesia remain critical to Asia's connectivity landscape, and their strategic importance will only grow as bandwidth demand accelerates, and new interconnection hubs are needed to deliver greater flexibility and route diversity," Slattery said. "We are building as much of that as possible into our system design and making that available to our cornerstone customers through APX West."

An ambitious timeline

Subco intends to complete all three systems in 2029. Slattery acknowledged the schedule is ambitious, "but it's achievable and it's necessary," given escalating demand for AI data centres and AI 'factories' across the region.

"People have been slow to understand that AI factories are dead without massive subsea connectivity to carry tokens from factory to customers," he said. "[That requires] hundreds and hundreds of terabits per second. That's why we are about to undertake the single largest subsea infrastructure build ever by a carrier in the Indo-Pacific."

That claim — the largest subsea build ever by a single carrier in the Indo-Pacific — is a company assertion rather than an independently verified figure. What is concrete is the design scope: three systems, each with 24 fibre pairs, a count well above the 8-to-16-pair configurations typical of recent regional cables, and a combined route length of about 24,100 km.

Why AI is reshaping cable economics

The announcement fits a broader pattern. Subsea cable investment has shifted from consumer internet traffic — once dominated by content providers' peer-to-peer and video demand — toward data centre interconnection, cloud regions and, increasingly, AI training and inference workloads. High-fibre-pair designs such as Subco's respond to that shift, concentrating capacity on routes linking AI compute clusters with end markets.

Slattery's framing of AI "factories" needing "hundreds and hundreds of terabits per second" underlines the scale gap between today's typical cable capacities and what clustered GPU data centres could require. Whether demand materialises at that pace by 2029 remains the central commercial risk for the build.

For Indonesia, APX West adds a second dimension to the story: more international bandwidth landing at Jakarta and Batam supports the country's push to become a regional data centre hub rather than merely a transit market. Singapore's role as Asia's premier interconnection point also features in Subco's rationale, with Slattery arguing new hubs are needed to ease concentration on existing landing points.

No cable suppliers, construction partners, capacity commitments or contract values were disclosed in Tuesday's announcement. Cornerstone customers are referenced in Slattery's statement but not named, leaving the commercial underpinning of the 2029 completion target open for now. Subco says it will provide further detail as the three systems move through planning and construction.