The 494m bridge, named the Europabrücke (Europe Bridge), hangs up to 85m above the Grabengufer ravine.
The Zermatt Tourist Board says it is the world's longest, although a 405m bridge in Reutte in Austria hangs 110m higher above the ground.
It replaces a previous bridge that had been damaged by rock falls.
The new bridge, whose cables weigh about eight tonnes, is equipped with a system to prevent it from swinging, the Zermatt Tourist Board said.
It forms part of a two-day hiking route between Zermatt and Grächen in southern Switzerland with views of the Matterhorn mountain.