Telstra's mobile network failed across the country for most of Wednesday, blocking 333 triple-zero calls, suspending every V/Line regional train in Victoria and knocking out payment terminals from Canberra buses to EV chargers. The company says a software defect was to blame, service was mostly restored by 4pm AEST, and the fault was not a cyber attack. The regulator has opened an investigation.
The failure began about 4:30am, when nodes in Sydney and Melbourne data centres that keep time across the mobile network stopped synchronising, causing intermittent call and data failures in every state and territory. "There was an update, and it did impact what's known as the GPS node, which caused the time to re-sync," Telstra chief financial officer Michael Ackland said. "This was not the result of a cyber incident." Asked how many of Telstra's 24.9 million retail mobile services were hit, Ackland said: "It could be tens of thousands, but I think it's more likely in the thousands."
The reach of the outage went well past handsets. V/Line suspended its entire regional network, which carries about 70,000 Victorians a day, NSW regional and intercity trains ran late, and the Australian Rail Track Corporation suspended services: a consequence, University of Canberra telecommunications academic Faraz Hasan wrote in The Conversation, of rail operators running train-to-control-centre communications over Telstra's 4G network. Some EFTPOS terminals, Canberra's MyWay+ ticketing and Chargefox EV charging went down with it.
The most serious failures were the emergency calls. Communications Minister Anika Wells and Emergency Management Minister Kristy McBain said the core triple-zero system kept operating but some Telstra customers could not connect to it. By 5:30pm the company had completed 395 welfare checks on failed callers: 167 confirmed safe by text, 143 by phone, 79 referred to state police for a physical check, and six who needed assistance, on Telstra's own figures. A separate fault kept some triple-zero calls failing into the evening; Telstra said overnight work reduced the error by about 90 per cent.
Wells drew the line the rules now draw. "This is not a triple zero outage. This is a Telstra retail outage that has affected their customers right across the country," she said, confirming the Australian Communications and Media Authority would run a full investigation. "Telstra will need to account for how and why this outage occurred." On the company's notification of government, she was shorter: "I think I would have liked to have heard earlier."
The rulebook Telstra will be measured against is new. Since November, carriers must ensure failed triple-zero calls can camp onto rival networks during outages, a reform written after Optus's 2023 and 2025 failures, and from June 30 this year (nine days before Wednesday's outage), every provider must publish a register of its resolved outages. Welfare checks on dropped emergency calls are a legal obligation, not a courtesy.
Telstra apologised: "We're deeply sorry for the impact this issue has had on so many people today," and said it would work with customers on remediation, which after its 2016 outages took the form of free data days. Its final update on Thursday morning called the issue close to fully resolved. What remains open is the ACMA investigation, and the question it will have to answer: how one company's software update stopped trains, payments and emergency calls in the same morning.
