AT&T Inc. is launching a new wireless home internet service, catching up to its rivals in one of the few promising areas where mobile carriers are putting high-capacity 5G networks to use.

Internet Air will be offered for for $55 a month in parts of 16 cities including Los Angeles, Philadelphia and Cincinnati, AT&T announced Tuesday.

The No. 3 US wireless carrier follows Verizon Communications Inc. and T-Mobile USA Inc. in pushing into home broadband, which is beamed into homes at a lower cost than landline internet. The phone companies’ invasion into territory traditionally held by the cable industry has put a dent into those providers’ subscriber numbers and helped offset plateauing wireless subscribers.

AT&T is still building out its 5G network — which promises significantly faster speeds and the ability to connect more devices — and is targeting select areas where it has enough network capacity to offer home wireless connections. More than half of AT&T’s 13.9 million broadband customers have fiber optic connections and most of the remainder are still on copper lines. The company plans to use wireless broadband to replace the old-line connections, among other things, Chief Executive Officer John Stankey said last month on an earnings call.

“It’s certainly going to help us in managing some of our installed base and, in particular, help us kind of make the transition out of some of our legacy infrastructure,” Stankey said, referring to the launch of Internet Air.

AT&T quietly rolled out a limited run of Internet Air to existing copper-based customers this year and is now extending the offering more broadly. It didn’t disclose the number of subscribers the service currently has.