More and more South Africans, especially those connected via fixed broadband connections, are turning to WhatsApp for calling as the mobile operators struggle with network quality amid intense load shedding.

During power outages, WhatsApp and other voice-over-internet apps often offer superior voice quality than regulator mobile calls as users can route the call over Wi-Fi and fibre. Although there was already a move to using WhatsApp for voice calls, load shedding has accelerated the trend, experts said. This is having a direct negative impact on voice revenues for South Africa’s mobile operators, which in some cases are seeing double-digit declines.

MTN South Africa is the latest mobile network to report a slump in outbound voice revenue. On Monday, parent MTN Group’s financial report for the first half of the 2023 financial year, blamed a 16% year-on-year decline in MTN South Africa’s voice revenues for the first quarter of 2023 on load shedding.

VoIP services like Zoom are becoming very common, not just in business but among families as well

“The extent of power outages in the country remained elevated, with 90 days of load shedding during the quarter, compared to 14 in the first quarter of 2022,” MTN said. “This heavily disrupted network availability … which affected MTN South Africa’s growth trajectory, especially in its voice segment.”

World Wide Worx MD Arthur Goldstuck told TechCentral that voice usage in itself is not in decline, even though telecommunications providers report that it is because of how they classify voice-over-IP (VoIP) calls as data usage, making them distinct from traditional voice calls.

“VoIP services like Zoom are becoming very common, not just in business but among families as well. I get very surprised if a family member calls me and it’s not via Zoom or WhatsApp,” Goldstuck said.

Regardless of how telecoms providers choose to classify VoIP services, internet calls are, nonetheless, a threat to traditional revenue streams for mobile operators.

Not alone

MTN is not alone in this battle. Vodacom Group CEO Shameel Joosub said in a recent interview with TechCentral that there is a big shift in consumer behaviour, with more and more voice being carried over the internet.

“Voice is transitioning to voice over data. More importantly, voice is being cannibalised by Messenger and WhatsApp,” Joosub said. “That is putting added pressure on telcos globally.”

In Vodacom Group’s 2023 annual report, it identified “adopting pricing strategies to counter declining traditional voice revenues” and migrating voice to data as key strategies to mitigate the risk.

A big driver of the uptick in the use of VoIP services is likely the increased fibre penetration to both homes and offices. Supplying backup power to a fibre router is relatively cheap, making it a popular way for consumers to mitigate the negative effects of load shedding on their ability to communicate.

“When people have Wi-Fi, either at the home or in the office, it is typically fibre and it will typically have a low-capacity UPS, too,” said Goldstuck. “Cellphone towers tend to fade fast and your only option is your fibre and Wi-Fi.”

Shameel Joosub

It is not, however, the resilience of fibre networks alone that has made VoIP services so reliable. As mobile broadband has evolved – from 3G to 4G to 5G – so, too, has the quality of VoIP calls.

“In the past, VoIP was shaky when mobile broadband speeds were in the 3G and low-4G ranges. Now that speeds are at the high-4G and 5G ranges, the quality of VoIP is often better than mobile,” said Goldstuck.

Vodacom’s Joosub agrees with Goldstuck’s analysis and told TechCentral that “voice more and more will be carried over data packets as you go to 4G and 5G”, he said.

MTN’s interim financial results suggest that VoIP calls are increasingly becoming the first option for voice connectivity as users continue to become more data-centric in their behaviour. Data contributed nearly half of MTN South Africa’s service revenue in the first half of 2023.