A new and distinct cultivar of Chrysanthemum plant named 'Yoerin', characterized by its upright, outwardly spreading and rounded plant habit; freely branching habit; dense and full appearance; uniform and freely flowering habit; small daisy-type inflorescences with elongated oblong-shaped ray florets; light purple-colored ray florets and bright yellow-colored disc florets; natural season flowering in mid-October in the Northern Hemisphere; and good garden performance.