| NOTICE TIME ZONE | Brisbane GMT+10 |
|---|---|
| STATUS (Open/Closed) | CLOSED |
| INCIDENT START DATE | 20260708 |
| INCIDENT START TIME (HH:MM) | Approx. 03:38 — triggering maintenance completed; service impact detected by Telstra at 04:20 |
| INCIDENT END DATE | 20260708 |
| INCIDENT END TIME (HH:MM) | 16:00 — initial mobile voice and data incident addressed |
| OUTAGE DURATION | Approx. 12 hours 22 minutes from the triggering maintenance event |
| INCIDENT CAUSED BY A 3RD PARTY? | YES |
| IF YES, NAME OF 3RD PARTY | TELSTRA |
| XCRM TICKET NUMBER | N/A |
| BRAND | N/A |
| INTERNAL PRIORITY | N/A |
| CUSTOMERS AFFECTED | XSTRA customers using Telstra mobile and 4G services. Nationally, Telstra reported that approximately 45% of mobile calls and data sessions were affected at the peak of the incident. |
| SITES AFFECTED | Multiple locations across Australia using Telstra mobile services; no single geographic site was responsible for the outage. |
| DESCRIPTION OF INCIDENT | A major national Telstra mobile network outage caused intermittent or unavailable mobile voice and data services. Affected users experienced failed calls, unavailable mobile data and, in some cases, an inability to connect normally to Triple Zero. Telstra confirmed that the incident was not caused by malicious activity or a cyberattack. |
| PRIMARY IMPACT EFFECT | Loss or degradation of Telstra mobile voice and data connectivity, including Telstra 4G services used by affected XSTRA customers. Sites relying on Telstra 4G for primary or backup internet connectivity may also have experienced degraded or unavailable WAN access. |
| SECONDARY IMPACT EFFECT | The wider national outage affected some Triple Zero calls, EFTPOS and other mobile payment services, transport communications and business operations. No separate secondary impact to XSTRA-managed infrastructure was identified. |
| EVENT TIMELINE | All times shown in Brisbane time, GMT+10. |
| WEDNESDAY 8TH JULY 2026 | |
| 03:38 | Telstra staff completed maintenance on a Network Time Protocol server while addressing a backup-power fault. The server was restarted as part of the approved procedure but returned with an incorrect date. |
| 04:20 | Telstra first detected an increase in mobile call failures and began investigating. |
| 04:38 | Telstra published its first service update confirming that it was investigating an issue affecting some mobile calls and data services. |
| 05:30 | XSTRA’s monitoring systems detected several customers whose Telstra 4G services were unavailable. Downdetector was checked and showed elevated Telstra outage reports: Telstra Downdetector |
| 06:38 | Telstra published a broader social-media notice advising customers that it was investigating the developing mobile network issue. |
| 07:05 | Downdetector reports continued to increase:  |
| 07:11 | Telstra isolated the affected time-synchronisation device and began progressively restoring the impacted network. |
| 07:15 | The outage received national media coverage: ABC News — Telstra mobile network outage |
| 07:20 | Telstra activated its Triple Zero Disruption Protocol Partner Bridge and began coordinating with emergency-service organisations and government stakeholders. |
| 10:00 | Telstra reported that most mobile calls and data services were working correctly. Restoration of the remaining services continued. |
| 13:00 | Telstra reported continued restoration progress and advised customers still experiencing problems to restart their mobile phone or device. |
| 13:30 | XSTRA’s monitored customer-facing Telstra 4G services were recorded as recovered or stable. Continued external monitoring remained in place. |
| 16:00 | Telstra advised that the initial mobile voice and data issue had been addressed. Some enterprise services and individual devices required additional time to reconnect. |
| 17:27 | Telstra publicly attributed the incident to a software defect and confirmed it was not a cyber incident. |
| THURSDAY 9TH JULY 2026 | |
| 10:38 | Telstra implemented a separate solution for the related issue affecting some Triple Zero calls. Telstra reported that no further welfare checks were required after this change. |
| RECOVERY & RESOLUTION | Telstra isolated the affected Network Time Protocol device at 07:11 and progressively restored the impacted network nodes. Most voice and data services were operational by 10:00, with the initial mobile network incident addressed by 16:00. Customers whose devices did not automatically reconnect were advised to restart them. A separate remediation for the related Triple Zero calling issue was implemented at 10:38 on 9 July. |
| XSTRA monitored affected Telstra 4G connections and confirmed recovery of the customer-facing services recorded in this incident. No changes to XSTRA-managed infrastructure were required. | |
| ROOT CAUSE | Telstra’s current likely root cause is a failure involving a Network Time Protocol server at its Exhibition Street network site in Melbourne. During approved maintenance for a backup-power fault, the server was restarted and an internal GPS timing card caused the server date to reset to 2006. The incorrect time then propagated into parts of Telstra’s mobile network, causing authentication and service failures. |
| Telstra believes the GPS card behaved unexpectedly because an earlier intentional equipment design change had not been properly documented. A required software update had also not been applied to the GPS card. Either the missing software update or properly documented maintenance instructions may have prevented the outage. Telstra’s external investigation remains in progress. | |
| CORRECTIVE & PREVENTATIVE MEASURES | Telstra isolated the defective time-synchronisation device, restored affected network nodes and implemented a separate correction for the related Triple Zero issue. Telstra has commissioned an external expert investigation to determine why the equipment change was not documented, why the software update was not installed and how its risk-management and maintenance controls must be strengthened. ACMA is also investigating the incident. |
| XSTRA should continue monitoring carrier services, regularly test 4G failover connections and recommend multi-carrier or fixed-line redundancy wherever loss of a single telecommunications provider would cause a critical business interruption. Critical voice and data services should not rely exclusively on one carrier. | |
| RESIDUAL EFFECT | No continuing impact to the XSTRA-managed services covered by this incident has been identified. Some devices may have required a restart to reconnect. Telstra’s external root-cause investigation and regulatory review remain open, so further findings or corrective measures may be published. |
| SOURCE REFERENCES | Telstra — Incident and restoration report Telstra CEO — Senate inquiry opening statement ABC News — Original outage report ABC News — Root cause and Senate inquiry |
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