Diakhaby made his first team debut for Lyon on 10 September 2016 in a Ligue 1 match against Bordeaux, playing the whole match in a 3–1 home loss.[4] On 30 November 2016, he scored his first competitive goal for the Lyon first team in a 6–0 Ligue 1 away rout of Nantes.[5]
On 23 February 2017, Diakhaby scored a goal (in the 89th minute) in the 2016–17 Europa League round of 32 second-leg 7–1 home win over AZ Alkmaar to register his first career UEFA Europa League or UEFA Champions League goal.[6] He also scored a goal in each of two legs of the 2016–17 Europa League round of 16 tie against Roma.
Valencia
On 28 June 2018, Diakhaby signed a five-year deal with Spanish side Valencia.[7] On 3 March 2024, he sustained a serious injury, diagnosed as a dislocated knee, following a collision with Aurélien Tchouaméni during a match against Real Madrid.[8]
International career
Diakhaby was born in France, but is Guinean by descent.[9] He is a former youth international for France. In 2022 however he decided to represent the home country of his parents, Guinea, and debuted for them against Egypt.