Álvaro Carreras was part of Real Madrid's U-15 and U-17 teams before signing for Manchester United in September 2020. At Old Trafford, the left-back mainly played for the U-23 team and was called up to Manchester United’s first team for the last four matches of the 2021/22 Premier League season. At the end of that season, Álvaro Carreras was named Manchester United’s U-23 Player of the Year.
In the 2022/23 season, the defender played for Preston North End on loan, registering six assists in 42 matches. In the summer of 2023, Álvaro Carreras temporarily moved to Granada in La Liga. With the Andalusian team, the left-back played 14 matches in the first half of the 2023/24 season before returning to Manchester United and then joining Benfica on loan.
