AT&T was, by some measures, the first carrier to roll out 5G wireless services in late 2018. However, it still only has a single 5G device, a $500 Netgear hotspot you probably won't be allowed to buy. The carrier is rolling its 5G ghost town in seven more cities today, bringing its total to 19.
The newly added markets are Austin, Los Angeles, Nashville, Orlando, San Diego, San Francisco, and San Jose. You won't get 5G signals in all parts of those cities, though. Like most carriers, AT&T is launching 5G on millimeter wave only. Those signals offer high download speeds but don't travel very far. AT&T says that lower frequency "sub-6" 5G will come next year.
If you live in one of AT&T's new 5G markets, good luck actually using 5G. The Netgear hotspot remains the only way you can access the new network, and AT&T won't sell it to just anyone. Currently, only select businesses and consumers have been able to use AT&T's 5G. We expect the Galaxy S10 5G to launch on AT&T later this year, and hopefully you won't have to ask nicely to buy one.