The Moroccan international agreed a four-year contract with the Greek club.
Advertisement
Advertisement
Louza played a key role for Watford last season, scoring seven goals and providing nine assists in 42 Championship appearances.
The 27-year-old featured for 20 minutes in a pre-season friendly against Fiorentina last month but did not play competitively this season.
Louza had previously captained Watford, although new boss Alessio Dionisi handed the armband to defender Mattie Pollock.
The African joined the Hornets from Nantes in 2021 and spent five months on loan at Lorient in 2024. He has made 81 appearances over the past two seasons and represents Morocco internationally.