File photo: Nadine Hutton.

Johannesburg - Vodacom, the wireless operator with the most subscribers in South Africa, said quarterly revenue increased 4.3 percent as customers used more data outside its domestic market.

Sales rose to 18.3 billion rand in the three months through June, the Johannesburg-based company said in a statement today.

Data revenue soared 23 percent to 3.6 billion rand as the company’s active data customers increased 37 percent to 25.3 million.

“Data and the international businesses have once again been the largest contributors to growth, and the entire business is seeing the benefit of our sustained investment program,” chief executive Shameel Joosub said in the statement.

Vodacom, which is 65 percent owned by Vodafone, is expanding its Internet and data services while adding small-to-medium sized business customers to offset declining voice sales from its home market, which is being squeezed by cuts in the rates it can charge for ending calls on its network.

South Africa sales advanced 2 percent in the quarter, while international mobile data revenue increased 51 percent to 636 million rand as the company added customers in Tanzania, Mozambique, the Democratic Republic of Congo and Lesotho.

The phone company’s active customers increased 16 percent to 59.6 million. - Bloomberg News