On 26 July 2018, following Deportivo de La Coruña's relegation from the La Liga, Schär signed a three-year deal with Newcastle United after the club had activated his £3 million buy out clause in his contract.
He made his debut for the club on 26 August 2018 in a 2–1 defeat to Chelsea. Schär scored his first goals for Newcastle against Cardiff City on 19 January 2019, netting twice in a 3–0 victory at St James' Park. He scored his third Newcastle goal against Burnley in a 2–0 win, opening the scoring with a 30-yard strike that would win Premier League and Match of the Day's February Goal of the Month competition. His fourth goal came in the final game of the season, and eventual 4–0 win over Fulham.