United States mobile networks have already rolled out some degree of 5G connectivity to millions of people, but more recently, AT&T and Verizon have been excited about deploying 5G on the C-Band spectrum they acquired in an FCC auction. After a few delays due to concerns from the Federal Aviation Administration (FAA) and some airlines, both carriers are switching on C-Band 5G service in select areas.

The C-band spectrum operates between around 3.7 and 4.2 GHz, offering a middle ground between the slow far-reaching bands (like those often used for LTE and sub-6GHz 5G) and fast short-range bands (like the ones utilized by mmWave 5G). Verizon and AT&T's rollouts are somewhat similar to T-Mobile's mid-band 5G deployments, which helped boost 5G speeds in some parts of the United States.

AT&T said in an announcement, "AT&T 5G already reaches more than 255 million people in more than 16,000 cities and towns, and AT&T 5G+ (using mmWave) is live in parts of more than 40 cities and nearly 30 stadiums and venues. C-Band spectrum complements those existing capabilities perfectly. Today’s introduction begins in limited parts of 8 metro areas across the U.S. It will expand rapidly as our thoughtful and efficient deployment ramps up throughout the year."

AT&T has enabled C-Band 5G in Dallas/Fort Worth, Houston, Austin, Chicago, Detroit, Jacksonville, Orlando, and Miami. However, you'll also need a phone updated to use C-Band 5G, which currently includes the iPhone 12/13 series and a few Android devices. The full list is below, as provided to XDA Developers by AT&T.

Verizon is also rolling out its C-Band 5G service today, which is now live for "more than 20 million households." The carrier has not publicly disclosed where exactly the deployments are, or what phones are compatible with its C-Band 5G. Customers also have to be on a "5G Get More," "5G Play More," or "5G Do More" plane to access C-Band — the cheapest "5G Start" wireless plan is left out.

Both AT&T and Verizon will use their existing millimeter-wave indicators in the status bar for C-Band connections — "5G+" for AT&T, and "5G UW" for Verizon. The rollouts have also affected global air travel.