Singtel confirmed last week that the company is in talks over a sale of its Australian subsidiary Optus.

The update from the Singaporean telco was given via a stock exchange filing last Thursday (July 30).

The filing came on the same day that the Australian Communications and Media Authority (ACMA) revealed that it had kicked off proceedings in the Federal Court against Optus Mobile Pty Limited (Optus Mobile) in relation to the September 18, 2025 Triple Zero outage.

"We can confirm we are currently in discussions with interested parties, but there is no certainty or assurance that any transaction will occur. Singtel will make an announcement if and when there are any material developments that warrant disclosure," Singtel said in the filing.

It follows an announcement in May from Singtel that the carrier was "open to working with potential Australian partners that align with its objectives of ensuring that Optus continues to be a strong alternative operator in the industry."

The carrier reiterated that desire in the filing last week as it looks to sell a minority stake in its Australian asset.

Singaporean telco Singtel acquired Optus back in 2001, and has fully owned the subsidiary throughout that time.

September's Triple Zero outage fallout rumbles on

The timing of the filing comes as Optus looks set to face the ACMA in court over last September's Triple Zero outage.

The carrier suffered a significant Triple Zero outage in September, during which four people died, while it's estimated that 600 customers were potentially impacted. Triple Zero (000) is Australia's main emergency service phone number.

It wasn't the first time Optus has suffered a significant outage that has impacted Triple Zero services. A year earlier, the carrier was slapped with an AU$12 million ($7.93m) fine for an outage in 2023. The outage, which happened on November 8, 2023, lasted more than 14 hours.

“The recurrence of a major network outage affecting emergency calls so soon after the November 2023 outage is a significant concern and one of the reasons the ACMA has decided to take this matter to court," said Nerida O’Loughlin, chair, ACMA.

“The ACMA will not hesitate to take strong enforcement action where alleged telco failures have jeopardized public access to the critical emergency call service."

In total, the ACMA notes that Optus breached two legal obligations more than 1,000 times during the Triple Zero outage on September 18, 2025. Each contravention could lead to a maximum penalty of AU$250,000 ($176,000).