Diaby was born in Senegal, but moved to Mataró, Catalonia at the age of four and went on to represent clubs of the region as a youth.
[1] He made his first team debut for UE Cornellà on 15 May 2016, coming on as a substitute in a 0–1 Segunda División B home loss against CF Reus Deportiu.
[3] On 28 July 2017, Diaby agreed to a one-year loan deal with Girona FC, being immediately assigned to the reserves in the third division.
[4] He made his first team debut on 28 November, replacing Carles Planas in a 1–1 away draw against Levante UD, for the season's Copa del Rey.
[12] The club entered discussions surrounding a new contract at the end of the season[13] and on May 30 announced he had signed a new two-year deal.