AT&T (NYSE: T) has acquired Wi-Fi network operator Wayport for $275 million. The deal expands AT&T’s Wi-Fi network to nearly 20,000 hotspots in the U.S. by adding locations at some Wyndham, Marriott Vacation Club and Four Seasons hotels; HealthSouth and Sun Healthcare locations; plus McDonald’s restaurants.

For a technology mostly shunned by U.S. carriers a couple years ago, Wi-Fi has quickly found its groove as a way for networks to offload heavy data usage. Where carriers were worried about lost data and voice revenues to Wi-Fi before, they’re now happy to welcome Wi-Fi capable devices on board (with the exception of Verizon) to ease congestion and traffic on their cellular networks. AT&T recently announced that its Wi-Fi network would be available for free to iPhone and BlackBerry Bold customers. Release.

Photo credit: flying.org.