Optus Triple Zero Outage

• On 18 September 2025, Optus experienced a major fault affecting the ability of its mobile customers to call the national emergency number 000 (also known as “triple-zero”).
• The fault was caused by a “routine firewall upgrade” (network upgrade) which ended up blocking emergency-calls traffic for some of its customers.
• The affected regions included parts of South Australia, Western Australia, the Northern Territory — and some accounts suggest callers in parts of NSW (via SA tower routing) were also impacted.
• Approximately 600 calls to 000 failed (or could not be connected) on Optus’ network during the outage window.
• Tragically, at least three people were confirmed to have died in circumstances linked to the outage — in SA and WA. One of the deaths was an eight-week-old baby in SA, although investigations caution that it is unlikely the outage was the direct cause in that case.

Why it’s serious

• Access to 000 is a critical public safety service — when it’s unavailable, lives are at stake. The fact that emergency calls failed, even if for a limited number of people, is highly concerning.
• This isn’t an isolated incident for Optus: the company had a large-scale outage in November 2023 during which more than 2,000 people could not access emergency services.
• There is major public and regulatory backlash: questions are being asked about how Optus monitors and safeguards its “emergency call” infrastructure, how it communicates with government/emergency services, and whether backup systems (fail-over) kicked in properly.

What went wrong (so far)

• The root technical issue was the firewall upgrade, which — according to Optus’ own statements and media investigations — caused the emergency-call routing to fail or be blocked.
• Normal calls (non-000) apparently were not significantly affected — meaning the failure was specific to the emergency call subsystem.
• The regulatory mechanism that allows a mobile phone to “camp on” to another network for 000 calls if its network fails (in some cases) did not function adequately in this event, or at least did not fully protect all users.
• Communication and notification to governments/emergency services was significantly delayed, which hampered timely welfare checks and response.

What’s being done / what’s next

• Optus has launched an investigation and has said it will publicly release what it found.
• Regulators are also involved: the Australian Communications and Media Authority (ACMA) and government ministers are pushing for accountability and stronger rules on critical-emergency networks.
• Optus announced it will ramp up automation and monitoring of its emergency-call systems and networks to try to prevent a repeat.

What you should know as a mobile user

• If you ever cannot get through on your network to emergency services (000), try using a different phone/network if available.
• In the future, check whether your carrier ensures “camp-on” or fallback to another network for 000 calls — this is an important safety feature.
• If you are in a location and your mobile network fails to connect to 000, it may be worth having alternate contact methods or informing someone you may need help.
• Keep an eye on the status updates from your provider (for example via their “Service Status” webpage) so if there is an outage you may be aware early.