In a unanimous decision, a three-judge panel of the Court of Appeals for the District of Columbia Circuit said that the data roaming requirements fall under the FCC's "broad authority" to manage the airwaves.
The same court is currently reviewing Verizon's separate challenge to the FCC's controversial net-neutrality rules, which bar Internet service providers from slowing down or blocking websites. Supporters of the net-neutrality rules say they are critical for ensuring an open and vibrant Internet, but critics consider them an illegal power grab.
The D.C. Circuit has already ruled against a previous attempt by the FCC to enforce the principle of net neutrality, and many legal analysts consider the court hostile to expansive views of the FCC's authority over the Internet. But Tuesday's ruling could make the commission more optimistic that its net-neutrality rules, a signature achievement of Chairman Julius Genachowski's tenure, will survive.
The commission has long required that cellphone service providers offer reasonable voice roaming terms to their competitors. Roaming occurs when subscribers travel beyond their own carrier's network and use another company's cell towers to complete a call.
The commission adopted an order last year that expanded those roaming rules to cover wireless Internet service.
Verizon sued, claiming that the FCC overstepped its authority under the Communications Act. Verizon said the rules represented an "unprecedented and unbounded theory of regulatory power over wireless Internet service."
But the court ruled that Title III of the Communications Act "plainly empowers" the FCC to expand its roaming rules to cover data. The court also rejected Verizon's claim that the rules treat cellphone carriers as "common carriers," which is prohibited under the Communications Act.