Telstra experienced a nationwide outage that disrupted mobile phone calls, data services, train operations, emergency‑call services and payment systems, including online payments and EFTPOS transactions. Prime Minister Anthony Albanese said there was no evidence of malicious activity behind the failure and described the incident as a significant national disruption. Telstra chief financial officer Michael Ackland said the root cause was unknown and expressed regret for the outage.

Accounts differ on the cause of the failure. A western source reported that servers at data centres in Sydney and Melbourne were identified as a possible source of the problem but the exact cause remained unknown. An Indian source later attributed the failure to a software defect and said it was not a cyber‑attack.

The Guardian reported that the outage disrupted traffic‑light operation. The BBC noted that servers at the Sydney and Melbourne data centres were identified as a possible source of the problem. GDELT reported that time‑synchronisation mechanisms across several nodes on Australia’s east coast were not working and linked the issue to time‑synchronisation systems within Telstra data‑centre servers. The Times of India reported Telstra’s later attribution of the failure to a software defect. Seven News cited the Australian Communications Consumer Action Network as saying the outage was more than an inconvenience and a reminder of how quickly an essential service can disappear, and also reported that about 90 % of calls and data had been restored roughly seven hours after the outage began. The BBC described Telstra as Australia’s largest telecommunications company.