Strong growth in mobile data continues to be the deliverer for Vodacom as the voice revenue shows signs of going into reverse in South Africa’s fast-maturing and increasingly competitive market.

For the three months ended 31 December 2012 — Vodacom’s third financial quarter — group mobile voice revenues rose by just 1,1% to R9,3bn.

In South Africa, where competition has intensified substantially in the past 12 months and where mobile termination rates — these are cross-network, carrier-level call fees — continue to decline through regulatory intervention, voice revenues fell by 2,2% year-on year to R7,6bn.

At the same time, Vodacom’s group mobile data revenues shot up by 23,3% to R2,6bn, aided by a 17,2% increase in South Africa to R2,3bn and a doubling elsewhere in Africa, albeit off a lower base, to R306m.

In South Africa, data now contributes 18% to service revenue, up from 15,1% a year ago. Data traffic grew by 29,8%, more than offsetting a 13,5% reduction in Vodacom’s effective price per megabyte over the past 12 months.

“Smartphones remain a key strategic growth driver, with active smartphones increasing by 29,2% to 5,8m devices,” Vodacom says in notes accompanying its quarterly trading statement, which was published on Wednesday morning.

“Smartphone net additions increased in the quarter compared to prior quarters, adding over 500 000 to our network largely supported by our working capital investment in handset financing.”

Data consumption on smartphones increased by 36,1% to an average of 138MB/month per device. Overall active data customers in South Africa climbed by 20,9% to 13,8m, representing 45,2% of the customer base. Just over 5m subscribers now use data bundles rather than ad hoc data.

Internationally, data now contributes 11% of service revenue, up from 5,3% a year ago. This has been driven by the take-up of mobile Internet services in all of Vodacom’s markets outside South Africa and increased penetration of mobile payments service M-Pesa in Tanzania. M-Pesa revenue now accounts for almost three-quarters of Tanzania’s overall data revenue and 14,1% of service revenue.