AT&T is once again slapping a price hike on its grandfathered unlimited data plans by $5, following the first instance of such a hike applied this past year.

The increase will affect AT&T's mobile subscribers who have been tied to the company's unlimited data plans for years after AT&T halted its availability to new subscribers.

AT&T Price Hike

This comes from a report by DSLReports published Monday, and the company has since given Ars Technica a confirmation of the report on Wednesday.

AT&T says that those who are still under a "legacy unlimited data plan" may choose to remain subscribed to it, but it will nonetheless increase by the aforementioned amount beginning March.

For seven years, the subscription model had been set at $30 per month until the company applied a $5 price hike in February last year. The new uptick brings the grandfathered unlimited data plan to a total of $40 per month, an amount, bear in mind, that's just for data. Voice and texting can balloon the total price up to $90 per month.

AT&T Wants You To Switch To Its Newer Data Plans

The company encouraged legacy data plan subscribers to shift to one of its new plans, most of which, if not all, have data caps. AT&T says that the newer plans have several benefits in store that are not present in grandfathered data plans. For instance, the newer subscription plans feature mobile hotspot connections, which allows a phone under the plan to share its internet connection with a separate device.

AT&T had stopped availability of unlimited smartphone data plans to new customers, even barring it from customers who were switching to a different plan. A new unlimited plan was introduced last year, but only those who were subscribed to DirecTV or U-verse TV got their piece of the pie.

Both Verizon and AT&T have snuck in — sneaking, still — sly measures to prevent people from going after unlimited data plans. The former is forcing customers to give up their unlimited data subscription if they use beyond 200 GB per month. The latter has introduced maneuvers to reduce the benefits of its grandfathered data plan. In 2011, AT&T revoked unlimited data plans from jailbroken iPhones that are used for unauthorized tethering. The company also throttled customers after using more than 3 or 5 GB for the remainder of the month, respective of what device was used to incur the data.

AT&T has lessened its volatile throttling measures, however, now only applying it after subscribers use up at least 22 GB of data in a month. This form of data-wringing from network providers, such as Verizon's, have not sat well with government agencies. Despite this, their attempts to reprimand and subsequently issue sanctions to prohibitive networks have so far been ineffective.

Any readers who are subscribed to AT&T's grandfathered unlimited plans? What do you think of the imminent price increase? Feel free to sound off in the comments section below!