Sprint announced today that it has turned on its 5G network in parts of four U.S. cities: Atlanta, Dallas-Fort Worth, Houston, and Kansas City. The carrier beat its previously announced May 31 deadline by a day, while maintaining that it will commence service in Chicago, Los Angeles, New York City, Phoenix, and Washington, D.C. “in the coming weeks.”

According to Sprint, each of the four initial cities has at least 150 square miles and 565,000 people worth of coverage, though the numbers are higher in most locations. Once all nine cities are online, Sprint says that it will coverĀ 2,180 square miles and 11.5 million people with 5G service.

In the Dallas-Fort Worth region alone, Sprint’s initial 5G footprint is 575 square miles with 1.6 million covered people, including cell towers in downtown Fort Worth, Irving, and North Dallas. For Houston, the carrier is claiming 165 square miles of 5G coverage, including downtown through the Memorial City Mall, servicing up to 800,000 people. And today’s Kansas City coverage includes 225 square miles with 625,000 people, ranging “from downtown Kansas City, MO, to Overland Park, KS where the company is headquartered.”

Sprint’s initial 5G network is based solely on 2.5GHz spectrum, usingĀ Massive MIMO radios that use 64 transmitters and 64 receivers at once. Each radio can simultaneously offer 5G and 4G service, which Sprint notes is LTE Advanced — the newer, faster version of 4G that AT&T has branded as “5G Evolution.” The carrier didn’t reveal its 5G performance levels, beyond describing them in both its promotional video and press releases as “blazing-fast download speeds.” It also says that it will support simultaneous 4G-5G connectivity for faster speeds.

There are, of course, a couple of hitches. While Sprint’s 5G services are now available to customers, its first two devices — LG’s V50 phone and HTC’s 5G Hub — don’t officially go on sale until tomorrow in the company’s retail stores, while Samsung’s Galaxy S10 5G is still slated for a Sprint release “this summer.” Additionally, Sprint’s merger with T-Mobile remains in a holding pattern, following which its 5G assets could be subsumed into a larger co-developed network. It’s unclear whether Sprint’s first 5G devices will be able to fully take advantage of all of the merged entities’ 5G spectrum, particularly the short-distance, high-speed millimeter wave frequencies that T-Mobile has said it will be using.

Update at 11:39 a.m. Pacific: Sprint is apparently setting low expectations for its 5G performance, telling Tom’s Guide that users should “see more than 100Mbps when you’re driving around with your phone,” but actually delivering between 171Mbps and 700Mbps depending on conditions — more commonly between 300 and 600Mbps.