On 11 July 2018, Bonetto was signed by Serie C club Prato on a season-long loan deal. On 4 October he made his debut for Prato as a substitute replacing Nicola Guglielmelli in the 60th minute of a 5–2 home defeat against Carrarese. On 15 October, Bonetto played his first match as a starter for Prato, a 3–2 home defeat against Monza, he was replaced by Lorenzo Liurni in the 70th minute. On 8 November he played his first entire match for Prato, a 0–0 away draw against Lucchese. Bonetto ended his season-long loan to Prato with 21 appearances and 2 assists, but Prato was relegated in Serie D.
