Two Broken Cables, One Repair Ship: Why Australia's Link to Asia Stays Slow Until November

On October 9, Australian network operator Vocus pushed back the repair dates for the two submarine cables connecting the country's west coast to Singapore and the rest of Asia. A repair vessel will now depart Singapore around October 22, the first cable is expected to be fixed around November 1, and the second around November 11. The previous plan had the vessel sailing on October 11, but permits, vessel scheduling, and undersea logistics have pushed everything back. The next status update is due on October 14.

The stakes are larger than a few slow websites. Indigo West has been out of service since August 7; Vocus's Australia Singapore Cable has been broken since early September. For more than two months, traffic between Australia and Southeast Asia has been squeezing through longer, more crowded detours: up through Japan, across the Pacific to the United States, and back again, adding hundreds of milliseconds of latency to connections that used to go direct.

The two breaks

The first fault hit on August 7, when shunt faults knocked out both Indigo West and Indigo Central, two systems that connect Perth with Singapore and Sydney. The faults appeared at almost the same time, in segments of cable lying inside the Perth Submarine Cable Protection Zone, where anchoring and dredging are prohibited to protect this infrastructure. Bevan Slattery, founder of SUBCO, the company behind the Indigo systems, posted vessel-tracking data on LinkedIn showing an oil tanker, the GEM Sapphire, making repeated erratic crossings over the protection zone around the time of the faults. SUBCO referred the matter to the Australian Federal Police as a potential crime, and the AFP has said the report is being assessed.

A repair vessel worked on the Perth end of Indigo West in early September, and the physical repairs were completed on September 16. Then came a stranger problem: when power was handed back to the landing station, traffic failed to restore. Testing had also found a separate shunt fault at the Singapore end of Indigo West. And on September 4, the second cable went down too: Vocus reported a break on its Australia Singapore Cable, a roughly 4,600 kilometer Perth-to-Singapore system. Testing from both landing stations located the break in Indonesian waters, about 615 kilometers from the Singapore end.

Why one cable has to wait for the other

This is where undersea repair stops being a technology problem and becomes a logistics puzzle. The ASC fault has formal priority, but on September 18 Vocus agreed to sequence the Indigo West repair first, and the reason is physical. Fixing ASC requires the damaged section to be powered down, and that section currently carries the temporary Layer 2 Ethernet capacity keeping restored services running through Jakarta. Power it down now, and that capacity disappears onto already crowded alternate routes. Restore Indigo West first, and its fresh capacity absorbs the rerouted traffic before ASC goes dark for surgery.

The vessel can only be in one place at a time. Under the original September schedule it would have departed Singapore on October 11 and finished Indigo West around October 24, then transited to the ASC site with ASC done by November 4. The October 9 update slipped all of that: departure around October 22, Indigo West around November 1, ASC marine works around November 3, and ASC completion around November 11. Indonesian permits remain a key dependency, along with sea conditions and the cable’s state once hauled up. As Vocus notes, none of these dates are guarantees.

The repair ship can only be in one place at a time, so the internet's healing here has a speed limit measured in knots.

How you fix a cable on the ocean floor

Finding the fault is the easy part. Engineers fire light pulses down the fiber and read the reflections, a technique called coherent optical time domain reflectometry, to pinpoint a break to within kilometers. That is how Vocus located the ASC fault about 615 kilometers from Singapore. The hard part is everything after: a specialized repair vessel must sail to the coordinates, grapple the cable off the seabed, haul it aboard, splice in a replacement section, and lay it back down. Permits must be secured first, and weather obeys no schedule.

It also matters what kind of fault it is. A shunt fault, the kind that hit Indigo, is an electrical failure: the cable's insulation is compromised and current leaks into the seawater, making the system electrically unusable though the fiber may be intact. A cable break, the kind ASC suffered, is a physical severing of the line. Both need a ship, but the procedures differ, which is why the industry keeps so few of these vessels and why two faults in one corridor create a queue.

How the traffic survives the detour

While the cables are down, the internet does what it always does: it routes around the damage. Vocus has been managing traffic across alternate paths, with temporary Layer 2 Ethernet services running from Perth to Singapore through Jakarta, plus a newly commissioned 100-gigabit path between Japan and Guam. But detours have costs. One Australian tech publication described the dual outage as stripping the country of up to 100 terabits per second of direct capacity, and traffic forced onto longer paths arrives hundreds of milliseconds later than the direct route it replaced. The symptoms are slow and uneven rather than a blackout: which sites feel slow depends on your provider, your destination, and which remaining pipe your traffic squeezes through. Australia's domestic internet is largely unaffected; the pain concentrates on traffic bound for Asia.

This is the same machinery that carried the Philippines through its own cable cut earlier this month, when carriers rerouted around a severed link within hours (see our earlier piece on the Philippines rerouting). The routing protocol that makes it possible, BGP, is worth understanding on its own (BGP). The difference in Australia is duration: rerouting is measured in hours, but physically repairing two cables in a permit-heavy corridor is measured in months.

Who guards the cables

The Indigo faults are a reminder that the threats to undersea cables are mostly mundane. The protection zone exists because anchors and dredgers are the historic enemies of buried cable, and the GEM Sapphire's track over the zone is exactly the kind of incident it was meant to prevent. Whether it was an accident or something worse is now a question for the AFP. Most subsea faults worldwide turn out to be accidents: dragging anchors, fishing trawlers, undersea landslides. Sabotage gets the headlines; statistics favor the anchor.

The bigger structural story is concentration. Australia's west coast has two direct cables to Asia, and for weeks neither has worked. Until the ship sails around October 22 and the permits clear, the detour is the route, and the internet between Australia and Asia keeps running on borrowed bandwidth.

References

Vocus, "Update on repairs to the Australia Singapore Cable" (September 2026; incident INC32585230 via SydneyITFix). SydneyITFix, "Chinese Websites Slow from Australia?" (October 10, 2026). Tech Business News Australia. AUNS (September 2026). Wikipedia, "Indigo (submarine cable system)".