Starting in January, Cablevision will tack on an additional $5 a month for the cost of its data service, which will result in an average increase of 3.2 percent.

The cost of Cablevision’s video and voice services will remain the same, and the price increase doesn’t apply to subscribers who are currently part of a promotional package, but the new pricing will go into effect once a customer’s promotion ends.

Cablevision said it was the first price increase for its data service in a decade. The Bethpage, N.Y., company also pointed out that it had recently spent $140 million on a network augmentation project and that it doesn’t implement bandwidth caps and consumption-based surcharges.

“Optimum Online is the gold standard of high-speed Internet service, offering customers blazing fast speeds, free access to the nation’s largest Wi-Fi network, and unsurpassed reliability and value,” said Gemma Toner, Cablevision’s senior vice president of broadband product management. “Over the last 10 years, we have made significant investments in our broadband product, recently affirmed by the FCC to deliver in excess of 100 percent of the speeds we advertise, along with advanced security, no usage caps, local news and information, and other key features.”

In announcing the price increase, Cablevision touted its Wi-Fi service, which is free to subscribers and has more than 50,000 hotspots in the New York Metropolitan area, plus access to Time Warner Cable and Comcast hotspots. Cablevision customers used its Wi-Fi to connect to the Internet more than 50 million times last month.

In last month’s third-quarter earnings report, Cablevision said it added 28,000 new data subscribers. Some subscribers could opt to use other data services due to the price increase, but Cablevision is betting that its data speeds and Wi-Fi service will keep them loyal.

With the trend of basic video subscriber losses continuing, data has become an increasingly important service to cable operators’ bottom lines. Cablevision, which sustained plant damage from Superstorm Sandy, is battling Verizon throughout most of its footprint.