AT&T this morning switched on its 5G wireless mobile network in 12 cities around the country, making it the first U.S. provider to launch portable 5G service for wireless devices.

Like Verizon, AT&T is in no hurry to sign up new customers for 5G service. Instead, it will only be available “in dense urban areas” for a handful of businesses and consumers invited to sample the service for free over the next 90 days.

“This is the first taste of the mobile 5G era,” said Andre Fuetsch, president, AT&T Labs and chief technology officer. “Being first, you can expect us to evolve very quickly. It’s early on the 5G journey and we’re ready to learn fast and continually iterate in the months ahead.”

Because cell phones equipped with 5G are not yet widely available, AT&T will sell its 5G service with a NETGEAR® Nighthawk 5G Mobile Hotspot device that will go on sale in the spring for $499. AT&T also intends to extract more money from wireless customers for its premium 5G experience. When service debuts, a 5G compatible data plan will start at $70 a month, including a 15GB data cap.

AT&T is not saying how fast its 5G network will actually be, only predicting it will be slower than the theoretical maximum speed of 1.2 Gbps, assuming nobody was using it. At an investor conference in early December, witnesses reported speed tests were averaging closer to 140 Mbps, which falls far short of the 5G Gigabit Hype the tech media has been breathlessly reporting.

AT&T’s launch switched on 5G service from selected city cell towers serving Atlanta, Charlotte, N.C., Dallas, Houston, Indianapolis, Jacksonville, Fla., Louisville, Ky., Oklahoma City, New Orleans, Raleigh, N.C., San Antonio, and Waco, Tex.. Over the next six months, AT&T plans to switch on 5G-equipped towers in Las Vegas, Los Angeles, Nashville, Orlando, San Diego, San Francisco, and San Jose.

AT&T’s 5G service will use traditional cellular frequency bands, and will effectively look like an incremental upgrade from 4G LTE. In real world performance terms, expect noticeably faster wireless speeds, but nothing close to what Verizon is offering with its fixed wireless 5G network, which relies on millimeter wave frequencies to deliver much faster service. AT&T’s 5G is portable, Verizon’s is not (for now). AT&T executives have been repeatedly skeptical about offering fixed wireless 5G.

AT&T hypes its forthcoming 5G network into the stratosphere. (1:44)