The powerhouse midfielder left West Ham United as a free agent back in June following their Premier League relegation, and has been on the hunt for a new club since then.
Traore - who came through the youth ranks at Barcelona and enjoyed a loan spell back in Catalonia in 2021 - has spent the majority of his career in England with stints at Aston Villa, Middlesbrough, Wolves, Fulham and West Ham.
Hs move to Deportivo is the first time the 30-year-old has played permanently in the first team of a LaLiga club.
His move to Galicia comes as part of an ambitious wider transfer project from the club after their return to the top-flight following an eight-year absence with former Arsenal and Barcelona striker Pierre-Emerick Aubameyang also joining from Marseille.