Verizon has entered an agreement to acquire the fiber internet provider Frontier in an all-cash deal valued at $20 billion. In its press release announcing the transaction, Verizon says the deal will “significantly expand Verizon’s fiber footprint across the nation, accelerating the company’s delivery of premium mobility and broadband services to current and new customers.”

The deal with Frontier may help Verizon regain its old Fios subscribers, after some of its wireline operations — including Fios fiber internet connections — were purchased by Frontier in 2015 for $10.5 billion. Frontier’s existing 2.2 million fiber subscribers in 25 states will now join Verizon’s approximately 7.4 million Fios connections in nine states. Frontier currently has 7.2 million fiber locations, and still plans to build out 2.8 million more by the end of 2026.

“The acquisition of Frontier is a strategic fit,” said Verizon Chairman and CEO Hans Vestberg. “It will build on Verizon’s two decades of leadership at the forefront of fiber and is an opportunity to become more competitive in more markets throughout the United States, enhancing our ability to deliver premium offerings to millions more customers across a combined fiber network.”