The Guinean, who joined the Reds from RB Leipzig in the summer of 2018, is leaving Anfield after five seasons, 129 appearances and 11 goals.
Keita lifted the Premier League, Champions League, FIFA Club World Cup, Emirates FA Cup, Carabao Cup and FA Community Shield during his time at the club, and received an emotional send-off from teammates and fans last month.
The next chapter of his career will see him return to Germany and the Bundesliga after signing a contract with Werder Bremen on Friday.
Everyone at Liverpool FC wishes Naby well at his new club.