By Frances Robinson

BRUSSELS -- Belgacom SA (BELG.BT) said third-quarter revenue from 4G mobile data grew as more customers started to use the service, and raised its guidance for full-year EBITDA.

Third-quarter net profit remained unchanged from a year earlier.

"Revenue from mobile services in particular showed a strong improvement thanks to the growing customer base and increased mobile data usage" which helped mobile average-revenue-per-user figures, said chief executive Dominique Leroy. She also cited "solid" TV revenue, which showed "double-digit growth in the third quarter."

In the third quarter, EBITDA rose 1.5% from the previous year to EUR431 million ($545.1 million), while net profit was unchanged at EUR156 Million. Sales were EUR1.49 billion, down 1.0% from the previous year, due to 6.1% revenue decline in Belgacom's International Carrier Services and the continued revenue erosion from its wholesale business.

Ms. Leroy, who took over at the start of this year, raised full-year EBITDA guidance for the group as she did last quarter. The company now expects the full-year 2014 figure to be "slightly positive" compared with an earlier forecast of a 1% to 2% decline from EBITDA of EUR1.7 billion last year.

Write to Frances Robinson at frances.robinson@wsj.com