A new and distinct cultivar of Chrysanthemum plant named 'Yoniagara Falls', characterized by its uniform and somewhat outwardly spreading plant habit; strong and freely branching growth habit; dark green-colored foliage; uniform flowering response and habit; typically grown as a spray-type; early flowering habit; daisy-type inflorescences with elongated oblong-shaped ray florets; white and red purple bi-colored ray florets and green-colored disc florets that develop slowly; and good postproduction longevity with plants maintaining good substance and color for about three to four weeks in an interior environment.