Back-to-back mobile network outages hit Singtel: Major telco disruptions in S’pore in recent years

SINGAPORE – Two back-to-back mobile network outages hit Singtel on March 16 and 17, affecting thousands of users in total.

The outage on March 16, which lasted more than eight hours, disrupted essential services in Singapore, including payments, ride-hailing and food delivery.

According to Singtel, a small number of mobile users were still facing mobile network issues on March 17, but the problems on the two days were unrelated.

The Straits Times looks at previous outages and fines imposed by the Infocomm Media Development Authority (IMDA) on telcos.

1. November 2025 – more than six hours

Singtel customers faced intermittent data connections for more than six hours on Nov 18, with the outage starting at about 3pm.

Downdetector, which tracks outages by collating status reports from a number of sources, had more than 1,600 reports at its peak in the afternoon.

Some users were unable to make or receive calls, while others had to tap public Wi-Fi networks to get through the day.

2. November 2024 – about two hours

M1 customers were unable to make or receive phone calls, and also could not receive one-time passwords via SMS due to an outage affecting the telco’s phone and messaging services on Nov 11.

Downdetector started picking up user complaints at about 1.45pm, and the number of complaints peaked at 1,773 at around 3pm. M1 said services were restored before 3.20pm.

3. October 2024 – more than four hours

An unprecedented islandwide disruption to Singtel’s telecommunications network on Oct 8 rendered hotlines for the Singapore Civil Defence Force and the police – along with those of hospitals and banks – unreachable.

The operator was subsequently fined $1 million over the fixed-line outage, which affected about 500,000 users for more than four hours.

An investigation by IMDA found that Singtel had placed two virtualised firewalls – for its fixed-line voice system, and a monitoring system managing home broadband routers and pay-TV set-top boxes – on the same hardware, causing them to share memory.

A surge in traffic on the monitoring system that day overwhelmed the shared memory, triggering intermittent failures in the voice system’s firewall. This disrupted the automatic failover to a backup system, causing calls to be dropped until Singtel fully redirected traffic to an unaffected voice system.

4. May 2020 – about 29 hours

During the Covid-19 circuit breaker period, M1 fibre broadband services were disrupted on May 12 and 13, affecting 38,000 subscribers in total. IMDA fined the telco $400,000.

Investigations found that on May 12, a corrupted profile database in M1’s broadband network gateway triggered a prolonged outage that disrupted services for around 18,000 subscribers for 23 hours.

A day later, on May 13, a separate incident affected up to 20,000 users for about six hours, after a software fault in M1’s network equipment disrupted the routing of internet traffic.

5. April 2020 – about nine hours

StarHub customers were affected by a major fibre broadband outage that lasted about nine hours, affecting their ability to work from home during the circuit breaker.

A staff member misconfigured a scheduled network migration and triggered the outage, according to IMDA.

The regulator noted that the disruption, which affected as many as 250,000 users, was avoidable, and pointed to lapses in StarHub’s oversight and supervision of its staff.

StarHub was fined $210,000.