South Africans are increasingly abandoning traditional mobile calls, and the shift is putting sustained pressure on one of the telecommunications industry’s oldest revenue streams.
- WhatsApp is a bigger threat to voice than spam calls
- Spam calls are making people afraid to answer
- Vodacom’s numbers show just how far voice usage has fallen
- Incoming calls tell a different story
- Average monthly call usage has dropped sharply
- Why traditional calls are losing the battle
- MTN and Vodacom are adapting to the change
- Voice is declining, but it is not disappearing
- The real cost of spam may be trust
- South Africa’s communications future is increasingly data-driven
MTN and Vodacom say voice communication remains important, but customer behaviour is changing rapidly as WhatsApp, Microsoft Teams and other internet-based platforms become the preferred way to communicate.
At the same time, an explosion in unwanted and suspicious calls is creating another problem: consumers are becoming increasingly reluctant to answer calls from numbers they do not recognise.
The result is a changing communications landscape in which traditional voice calls are losing ground to data-driven alternatives.
WhatsApp is a bigger threat to voice than spam calls
Spam calls are certainly contributing to the problem, but MTN South Africa says they are not the main reason for the long-term decline in voice revenue.
The bigger structural change is the migration from conventional cellular voice services to internet-based communications.
WhatsApp has become deeply embedded in everyday communication in South Africa, allowing users to make voice and video calls using mobile data or Wi-Fi rather than conventional cellular minutes.
Microsoft Teams and similar platforms have also expanded the use of internet-based calling, particularly in professional environments.
This shift changes the economics of telecommunications.
A traditional mobile call generates voice traffic through the operator’s network. A WhatsApp call, by contrast, primarily consumes data.
That means consumers can continue making large numbers of calls while simultaneously reducing their reliance on traditional voice services.
MTN said its South African business had recorded a gradual decline in voice revenue over recent years, reflecting changing customer behaviour and the growing preference for data-based communication.
The company said the adoption of platforms such as WhatsApp and Microsoft Teams had significantly influenced the trend.
Spam calls are making people afraid to answer
There is, however, another layer to the story.
Even when a person wants to make or receive a conventional call, the growing volume of spam and suspicious calls can make them reluctant to answer.
For many smartphone users, an unfamiliar number now triggers a question: Is this an important call, or is someone trying to sell me something, scam me or obtain my personal information?
That uncertainty has consequences for legitimate callers as well.
MTN said there had been a noticeable change in the way customers respond to calls, including greater reluctance to answer unknown numbers.
The operator attributed this to several factors, including changing communication habits and broader concerns surrounding spam calls.
Importantly, MTN does not regard spam as the primary driver of declining voice traffic and revenue. Instead, it sees spam as an indirect contributor that can discourage customers from engaging with legitimate calls.
That distinction matters.
The decline in traditional voice usage would probably continue even without spam because customers have already changed how they communicate. But persistent nuisance calls can accelerate the decline by undermining trust in the traditional telephone system.
Vodacom’s numbers show just how far voice usage has fallen
Vodacom’s financial data provides a clearer picture of the scale of the transformation.
An analysis of the company’s South African voice traffic over its 2021 to 2026 financial years shows that total voice traffic fell by 12.63%.
The decline represents a reduction from 68.455 billion minutes in 2021 to 59.810 billion minutes in 2026.
That is a substantial contraction in traditional voice usage.
The biggest contributor was outgoing traffic.
Outgoing voice minutes fell by 17.74%, dropping from 57.586 billion minutes to 47.371 billion minutes during the five-year period.
In other words, South Africans are not simply receiving fewer calls. They are making substantially fewer conventional mobile calls as well.
Incoming calls tell a different story
Interestingly, Vodacom’s figures show that incoming voice traffic moved in the opposite direction.
Incoming voice minutes increased by 14.44%, from 10.869 billion minutes in 2021 to 12.439 billion minutes in 2026.
That creates an important distinction.
The overall decline in voice traffic is being driven primarily by falling outgoing calls rather than a collapse in incoming calls.
This could reflect the changing role of the traditional phone call.
Consumers may increasingly use WhatsApp and other platforms when they actively want to contact someone, while conventional cellular calls remain an important channel for receiving calls from businesses, institutions, customers, family members and people who have not shifted completely to internet-based calling.
But the growing prevalence of spam means even those incoming calls face another obstacle: people may simply refuse to answer.
Average monthly call usage has dropped sharply
Vodacom’s subscriber data provides perhaps the clearest indication of how individual behaviour has changed.
Average monthly voice usage among Vodacom South Africa subscribers declined from 136 minutes in 2021 to 108 minutes in 2026.
That represents a drop of roughly 21%.
The decline was particularly pronounced among postpaid customers.
Their average monthly voice usage fell from 195 minutes to 121 minutes over the five-year period.
That is a reduction of approximately 38%.
Prepaid customers also reduced their traditional calling, although the decline was less severe. Their average monthly usage dropped from 126 minutes to 105 minutes.
The figures demonstrate that the move away from conventional voice calling is not limited to one customer segment.
Why traditional calls are losing the battle
The smartphone has effectively transformed the mobile phone from a device primarily designed for voice communication into a portable internet terminal.
That distinction is increasingly important.
For years, mobile operators built their businesses around voice, SMS and, eventually, mobile data. Today, many of the services that once generated voice and messaging traffic are delivered through applications operating over the internet.
A consumer can send a message, make a voice call, start a video call, share documents and participate in a group conversation without using conventional voice or SMS services.
The mobile network is still essential because the customer needs connectivity.
But the commercial value has shifted from what the customer does on the network to how much data the customer consumes to do it.
That is why operators can experience declining voice revenue while simultaneously seeing strong demand for mobile data.
MTN and Vodacom are adapting to the change
The operators are not treating the decline in voice as the end of mobile communication.
Instead, they are adapting their businesses around the broader shift towards data.
MTN said it continues to encourage customers to use call-identification tools and to be cautious about sharing personal information online or through digital services.
The company also said it was working with regulators and industry bodies to improve the safety and trustworthiness of communications in South Africa.
Vodacom similarly described spam calls as an industry-wide challenge while acknowledging the broader migration towards over-the-top, or OTT, communication services.
Vodacom spokesperson Byron Kennedy said outbound voice minutes in South Africa declined 6.4% in its latest quarter, describing this as evidence of an ongoing migration towards OTT services.
The company nevertheless expects voice to remain an important service.
That may sound contradictory, but it reflects the reality of telecommunications today: a service can be declining without becoming irrelevant.
Voice is declining, but it is not disappearing
There are still situations where a conventional phone call is difficult to replace.
Emergency communication, customer service, business calls, healthcare-related communication and contact with people who are less comfortable with internet-based services all remain important use cases.
There is also an important reliability consideration.
Internet-based calling depends on data connectivity and the performance of the application being used. Traditional cellular voice services remain a distinct communications channel and can be valuable when users need a straightforward call without relying on a particular platform.
For Vodacom and MTN, the challenge is therefore not simply to replace voice.
It is to make sure that declining voice usage is offset by growth in areas such as mobile data, digital services and other higher-value offerings.
The real cost of spam may be trust
The most interesting part of the trend may not be the revenue lost from fewer calls.
It may be the erosion of trust.
When consumers receive repeated unsolicited calls, they begin treating unknown numbers as potential threats rather than opportunities for genuine communication.
That can affect everyone from businesses attempting to contact customers to individuals waiting for an important call.
The smartphone’s caller-ID and spam-detection features have consequently become increasingly important. They are no longer merely convenience tools; they form part of the wider battle to keep voice communication usable.
If consumers reach a point where they routinely ignore unknown numbers, legitimate callers may increasingly need alternative ways to establish their identity before a conversation even begins.
South Africa’s communications future is increasingly data-driven
The numbers from Vodacom provide a useful snapshot of a much larger transformation.
Between 2021 and 2026, total voice traffic declined by more than 12%, outgoing voice traffic fell by nearly 18%, and average monthly usage per subscriber dropped from 136 minutes to 108 minutes.
At the same time, internet-based communication platforms have become increasingly embedded in everyday life.
Spam calls have added another layer of disruption, encouraging consumers to screen or ignore unfamiliar numbers.
For MTN and Vodacom, this does not mean South Africans are communicating less.
They are communicating differently.
The traditional telephone call is gradually becoming just one option within a much broader digital communications ecosystem. WhatsApp, Microsoft Teams and other OTT platforms have shifted much of the activity that once generated voice traffic towards mobile data.
The irony is that the very networks experiencing declining voice usage remain essential to the transition. The calls may no longer travel through the traditional voice channel, but the data carrying them still needs a mobile or broadband connection.
For consumers, the change is simple: fewer minutes, more data.
For mobile operators, however, that shift represents one of the most significant transformations in the economics of telecommunications.
