Virgin Mobile USA will begin throttling the speeds of heavy data users in October amid a widespread shift by wireless operators toward tiered data plans.

The prepaid operator will still offer unlimited data plans, but will reduce network speeds for customers who use more than 2.5 GB in a month. Less than 3 percent of Virgin Mobile subscribers use more than 2.5 GB per month, according to statistics on current usage patterns provided by the company.

Virgin Mobile's plan mirrors a similar approach taken by T-Mobile USA, whose plans throttle users' speeds after they reach their monthly data cap.

Virgin Mobile Vice President David Trimble said in a statement that the data caps were necessary to rein in network-clogging data use by some customers.

"We are all facing the same situation and this is the best way for Virgin Mobile to maintain the best network experience as data usage explodes," Trimble said, referring to recent moves to cut unlimited plans at T-Mobile, AT&T and Verizon. "We believe this adjustment – with no hard cap or overage charges for more usage – gives the most value to the largest group of consumers. It's important to Sprint and the Virgin brand that we be as up-front as possible with our customers."

Sprint, which owns Virgin Mobile, is the last national operator to offer unlimited data plans. AT&T ended its unlimited plans last summer; Verizon Wireless followed suit with tiered plans last week.

Sprint has not taken a move to tiered pricing off the table and has repeatedly stated that unlimited plans remain an important draw for new customers. Virgin Mobile's decision to cap data usage may suggest that Sprint is taking a close look at shifting away from all-you-can-eat data.

Virgin Mobile's decision to cap data use came amid a broader shakeup in prices.

Virgin Mobile also announced today it will change its Beyond Talk plans on July 20. The company will charge $35 for its current $25 unlimited data plan with 300 voice minutes, but drop the plan's additional $10 charge for BlackBerry devices.

A similar change was made to the $40 unlimited data plan with 1,200 voice minutes, which will cost $45 but no longer charge $10 extra for BlackBerry phones. Virgin Mobile dropped the price for its all-you-can-eat voice and data plan from $60 to $55, and also ended the $10 BlackBerry charge.

"Adjusting these rates ensures that our Beyond Talk customers can continue to enjoy the best value overall in the market for Android devices with unlimited data and messaging," Trimble said.

Customers already on the Beyond Talk plans can keep their current rates as long as they don't let their account expire, and can keep their current plans if they move to a new device.