Comcast announced Xfinity Mobile on Thursday, a new wireless service that will be available for its nearly 25 million broadband customers.

The company, parent company of NBCUniversal, is hoping the new service will lock in existing customers as well as attract new ones, going after the 130 million mobile phone lines in places where Comcast offers services.

The company says the service is "designed for the way people use their phones today, with Internet and data at the center of the experience."

"Wireless is hyper competitive , we will measure our success very differently than other wireless carriers. How we approach the marketplace will be in packaging and bundles, and we'll approach our existing customer base," said Dave Watson, CEO of Comcast Cable.

Comcast is not taking a Wi-Fi-first approach, but is pairing 4G LTE via Verizon's network along with Comcast's 16 million Wi-Fi hotspots, to which the service will automatically connect.

The four major telecom companies have been battling over prices and offering different features to distinguish their services. Comcast expects this new business to be profitable, but at the same time doesn't aim to compete directly with the traditional wireless carriers. Rather, the goal is to use the new service to build its relationship with its core subscribers.

"One thing we're looking at now is retention — it's key for us," Watson said. "It will be designed to support the core cable business."

XFinity Mobile is designed to be flexible and a good deal for Comcast's customers: Xfinity Internet customers get five lines with no line access fees, with unlimited talk and text at no extra cost. And unlike most wireless services, customers can switch back and forth between data options at no extra cost.

Comcast customers can subscribe to unlimited cellular data for $65 a line — or $45 per line for customers with the best X1 packages. The alternative is to pay $12 per gigabyte of cellular data on all lines on an account each month.

Xfinity Mobile makes it easy to watch video through other Xfinity apps, including up to 200 live TV channels with the XFinity Stream app, or controlling their home device with the XFinity Home app.

At launch, Xfinity Mobile will be available on the most popular devices, including the iPhone 7 family, the Samsung Galaxy S8, and the LG XPower. The service will first launch with an employee trial, followed by a nationwide rollout to its customers as part of the bundle beginning later in the second quarter.

Disclosure: Comcast is the owner of NBCUniversal, the parent company of CNBC and CNBC.com.