 Opening the 2018–19 season on the Flyers roster, Folin continued to play in a bottom pairing role appearing in 26 games with Philadelphia, recording two assists, before he was traded with Dale Weise to the Montreal Canadiens in exchange for David Schlemko and Byron Froese on 10 February 2019.On 18 April, he signed a one-year contract extension with the Canadiens.Folin was waived by the Canadiens on 5 January 2020 and was reassigned to the Laval Rocket.