PUBLISHED ONOctober 20, 2026 9:30 AMBYSean LerThe Infocomm Media Development Authority (IMDA) has imposed a financial penalty of $1 million on Singtel Mobile for mobile service disruptions in March that affected about 720,000 mobile consumer and business subscribers.
The disruptions over a three-day period on March 16, 18 and 19 were within Singtel's control to prevent, the regulator said in a statement on Tuesday (Oct 20), highlighting that they were not due to a cyberattack.
On April 7, Minister for Digital Development and Information Josephine Teo, had said in a parliamentary reply that IMDA was investigating the incident, emphasising that service providers are required to ensure that service incidents are resolved within one hour.
Telcos who are unable to do so may face enforcement action and have financial penalties imposed, the minister stated, adding that service providers are also required to conduct regular audits on key telecom infrastructure for resilience.
In its statement, IMDA said that the March 16 disruption was caused by a chiller system failure at a Singtel Exchange.
This, in turn, caused the mobile network equipment at the Exchange to overheat and shut down.
The regulator noted that a Singtel vendor had failed to adhere to standard operating procedures that required them to reopen a manual valve controlling water flow after a scheduled maintenance.
It also found that Singtel did not actively monitor its manual valves or water flow to the chiller system.
"The service disruption on 16 March 2026 could have been prevented if Singtel had implemented robust frameworks, procedures, and systems to better monitor the operations of its chiller system at the affected Exchange," IMDA stated in its findings.
Meanwhile, the March 18 and 19 disruptions arose after 5G mobile traffic was redirected from the affected Exchange to another Exchange.
The increased 5G mobile traffic load, coupled with a disabled network packet optimiser and a software bug at the other Exchange, resulted in intermittent connectivity for some Singtel subscribers during the evenings on both days, IMDA stated.
In this instance, the disruption could have been prevented if Singtel had exercised greater diligence to ensure that the other Exchange was able to handle the increased traffic load, the regulator said.
IMDA said it took into account the scale and impact of the disruptions in determining the financial penalty, while also considering Singtel's actions.
These include its cooperation during investigations, effort to progressively restore mobile services for affected subscribers, and the goodwill rebates of $5 to $10 which amounted to around $8 million.
Singtel has since taken remediation measures to prevent a recurrence of the incidents by enhancing maintenance procedures and monitoring for the chiller systems, and rectifying the systems in the other Exchange.
It has also conducted exercises to better test its network failover effectiveness.
The regulator said it holds telcos which are key service providers to "a high level of service reliability".
"These service providers are required to plan, design and operate resilient networks, and put in place measures to ensure speedy recovery with minimal inconvenience to end-users in the event of a disruption.
"IMDA will not hesitate to take strong action under the Telecommunications Act, including imposing financial penalties, should any lapses be identified," IMDA added.
In 2025, Singtel was similarly hit with a $1 million fine for a nationwide landline outage that disrupted calls to public institutions and emergency services on Oct 8, 2024.
For about four hours that day, about half of the calls made to public service hotlines — including government agencies, banks and hospitals — could not be connected. The police and Singapore Civil Defence Force had urged the public to contact them via SMS instead.
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