Subco, an Australian submarine cable developer, said Tuesday it will build three new cable systems totalling roughly 24,100 km, all of them targeted for service in 2029. The shortest on paper is the one that matters to Indonesia. APX West runs 4,600 km from Perth to Singapore on 24 fibre pairs, with branches that drop into Jakarta and Batam.
Indonesia is in the middle of a fivefold capacity build, and it cannot finish that build on bandwidth alone. Maybank Investment Bank, citing IDPro estimates, put national data center capacity at 637 MW as of May 2026 and forecast about 2.7 GW by 2030. Brights Research counted roughly 580 MW of installed IT capacity in the first half of 2026 and projected 3.5 GW by 2030. The two houses land on different endpoints. They land on the same starting point.
Subsea pipe is what turns that starting point into something a hyperscaler will actually sign for. Subco founder and co-CEO Bevan Slattery framed the build in exactly those terms. "People have been slow to understand that AI factories are dead without massive subsea connectivity to carry tokens from factory to customers," he said. He put the requirement at "hundreds and hundreds of terabits per second."
24 fibre pairs, three systems
Most regional cables built over the past decade carry 8 to 16 fibre pairs. Subco is specifying 24 in each of the three new systems. That density sits above the current regional norm, and it says something about who is paying for the build.
Subsea investment has moved off consumer video and peer-to-peer traffic and onto data centre interconnection, cloud regions, and inference workloads. A 24-pair system concentrates capacity on the routes that link GPU clusters to the markets buying them, instead of spreading thin pairs across a mesh designed for streaming. Australia's Firmus showed what that shift looks like when it commits money. Firmus agreed on September 3 to spend US$300 million over 25 years for up to 150 Tbps on Subco's APX East system, a roughly 13,000 km Sydney-to-California route aimed at the fourth quarter of 2028.
The largest of the three new systems, APX East-2, is a planned 10,000 km run from Guam to Los Angeles. Subco says it supplies route diversity from the United States to both Japan and Australia through 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," Slattery said.
APX North covers 9,500 km from Sydney to Japan, also routing through Guam. Switched branching units will let selected fibre pairs bypass the Guam landing station, which is how Subco intends to offer a direct Australia-to-Japan path rather than making traffic touch down on the way. APX West is the shortest of the three at 4,600 km and the only one reaching Indonesian waters. Its design lets fibre pairs switch in and out of new interconnection hubs in Jakarta and Batam instead of terminating at a single landing point. "Singapore and Indonesia remain critical to Asia's connectivity, and their strategic importance will only grow as bandwidth demand accelerates," Slattery said, adding that new hubs are needed to deliver greater flexibility and route diversity.
Batam's pipeline runs straight into the power grid
Bandwidth arriving in Batam does not fix what actually slows the island down, which is electricity. Maybank put Batam's live data center capacity at about 134 MW against a build plan of 1.3 to 1.8 GW, compiled from public reporting. The island has roughly 0.9 GW of installed generation, with 860 MW of new plant capacity planned by 2032 under RUPTL, not counting solar panels. That arithmetic is tight.
It explains why Coordinating Minister for Economic Affairs Airlangga Hartarto talked about the grid rather than the network when he opened the Nongsa Changi Cable linking Batam to Singapore. He said Batam's data center sector is growing about 22% a year against a national average near 19%. He listed what is already committed: a BW Digital facility at Nongsa Digital Park with capacity up to 120 MW, a 450 MW hyperscale campus from Singapore's DayOne, and an Oracle cloud region sited at Nongsa.
New fibre on the seabed does nothing for any of those projects if the substation is not ready. It does give them a second way out of the country, and a second way out is what international tenants price. Hartarto counted 235.26 million internet users and around 99.5 million broadband subscribers in Indonesia, and pointed to geothermal in Sumatra and solar on Batam as the supply options. The ministry is pushing a generation expansion of up to 100 GW in cooperation with Singapore.
What Subco left out
The announcement came without a cable supplier, a construction partner, a contract value, or a capacity commitment. Anchor customers are referenced in Slattery's statement but not named. Subco said more detail will follow as the systems move through planning and construction, and it has not filed for a US cable landing licence yet.
That gap is worth naming. Firmus put a number and a signature on APX East. Nobody has done that publicly for APX West, APX North, or APX East-2. It's not obvious that a 2029 date holds across three systems at once with no supplier named and no cornerstone customer announced, and Subco has not shown its work on that schedule.
Slattery's claim that this is the largest subsea infrastructure build ever by a single carrier in the Indo-Pacific is a company assertion rather than an independently verified figure. The design scope is concrete enough on its own: three systems, 24 fibre pairs each, about 24,100 km of route.
Indonesia is not the only buyer
The Indo-Pacific build is one line in a much longer wave. Meta announced Petal in September, a 7,000 km system from the United States to France that it says will be the first to carry a petabit per second across an ocean, using two-core fibre from Sumitomo Electric and construction by NEC, in service 2029. EXA Infrastructure announced a 6,552 km, 24-fibre-pair system from New Jersey to Brean in the UK, with up to 500 Tbps of design capacity and a target of the fourth quarter of 2029.
Closer to home, a consortium including Microsoft, Lightstorm, Tata Communications and NEC plans a 3,600 km cable from Machilipatnam in India to Malaysia and Singapore. Lightstorm CEO Amajit Gupta told Capacity that it should be operational in the fourth quarter of 2029. Telecom Gazette reported the Subco announcement, and our cloud and edge desk has been tracking the capacity side of the same story.
Undersea cables carry roughly 95% of the world's internet traffic, according to TeleGeography. Capacity ordered in 2026 and 2027 enters service around the same time Indonesia's announced gigawatts are supposed to come online, which means the two schedules are now the same schedule.
Where this goes next
Slattery conceded the 2029 target is aggressive, "but it's achievable and it's necessary." For Jakarta and Batam the useful question is not whether the cable arrives. It is whether the megawatts land first.
Subco's next disclosure milestone is a named supplier and a named anchor customer for APX West. Until then, the Jakarta and Batam branches are a design drawing with a date on it, and Indonesia's regional data centre ambitions still sit downstream of a grid connection that no cable can substitute for.