On 14 August 2018, Aina joined Italian club Torino on a season-long loan after signing a new three-year deal with Chelsea. He made his Serie A debut a few days later in Torino's 0–1 opening day defeat at home to Roma, coming on as a substitute in place of fellow right-back Lorenzo De Silvestri who went off injured after just 25 minutes. Aina scored his first goal for Torino in a match against Udinese on 2 February 2019. Aina made 30 Serie A appearances in what was a strong season for Il Toro, whose seventh place finish secured a Europa League qualifying spot.