On 3 July 2013, Mannone signed a two-year contract with Sunderland, for an undisclosed fee. Mannone started both of Sunderland's matches in the Premier League Asia Trophy in pre-season, but Keiren Westwood was preferred to him for the opening league game of the season against Fulham. After featuring in the League Cup, Mannone made his league debut for the Black Cats in a 1–0 loss at Hull, replacing the injured Westwood. Mannone retained his place for a 2–1 cup win over Southampton, and made his first league start in a 1–0 home win over Manchester City.