SAN FRANCISCO -- AT&T is raising the price of its unlimited data plan by $5, joining a recent wave of wireless carriers trying to price customers out of limitless mobile Internet. The price hike will take effect in February and bring the cost of the plan to $35 per month, with texting and calling excluded. 

The price hike will be the first since AT&T began offering the unlimited data plan alongside the original iPhone. The change was reported by 9to5Mac and by the Verge and has been confirmed by AT&T. As many as 6 million customers are believed to still be on the plan, which the carrier stopped offering to new customers in 2010. 

“We are adjusting our rate for unlimited data customers," an AT&T spokeswoman said in a statement. "This is the first price increase to our grandfathered unlimited data plans in seven years."

For years, AT&T and Verizon have been trying numerous tactics to persuade grandfathered customers of their unlimited data plans to switch to different options. For a while, AT&T throttled, or slowed down, the speeds of unlimited data after customers reached the 5 gigabyte mark, but the carrier decided to change that limit to 22 GB in September being threatened with a $100 million fine by the Federal Communications Commission for misleading customers.

Without the ability to throttle customers into switching plans, AT&T appears to be going with the tactic of pricing them out. This strategy has recently been employed by others in the wireless market. Verizon in October decided to raise the price of its unlimited data plans by $20 per month while T-Mobile a few weeks ago announced it had raised the price of its unlimited LTE data plan by $15 per month

At $5, AT&T's price increase is the most modest of the bunch, but it sets a precedent that the carrier can raise the price of the plan any time it wants.