AT&T Inc. (NYSE:T) announced that the company is rolling out another price hike to its unlimited data plans, marking the third price hike from the company in three years.

The carrier announced that customers who have had a decade-old grandfathered unlimited data plan will now have to pay an additional $5 per month, making the new price $45 a  month. The price was $30 monthly for seven years until the company raised it to $35 in February 2016, followed by another $5 bump to $40 a month in January 2017.

The new price increase will affect AT&T device owners next month. “Customers who have a grandfathered $40 data plan will receive notifications of a $5 per month rate increase for the data plan,” AT&T said in the price increase announcement. “The rate increase will take effect starting with the customer’s July, 2018 service.”

The $45 monthly fee applies to users with wireless data only as they will have to pay additional fees for phone calling and texting, which will nearly double the overall price. The company appears to be making the increase in order to encourage customers to move to newer plans.

AT&T said that is customers should “learn more about the benefits of our currently available unlimited rate plans.” The carrier added that customers who switch to a different plan “will not be able to switch back to their current grandfathered unlimited data plan in the future.”

T stock gained 0.2% on Friday.