The 35-year-old star confirmed her departure in a note on Instagram.
"Thank you SNL for 7 years of laughs, love and incredible memories. It has been a dream come true. And thanks for this goodbye sketch at the table, Colin," she wrote alongside a farewell note.
Bayer joined the cast of SNL as a featured player in fall 2010.
Some of her most popular recurring characters on the show include Jacob the Bar Mitzvah Boy, who appears on Weekend Update; Rebecca Stern-Markowicz, a co-host of J-Pop America Fun Time Now; Rachel from "Friends" and child actress Laura Parsons, reported Deadline.