The 36-year-old, who played at three World Cups, has joined Sevilla on a one-year deal with a potential extra season, the La Liga outfit said.
Azpilicueta played eleven seasons at Chelsea between 2012-2023, racking up 508 appearances, winning the Premier League twice and the European Champions League.
He was captain of Chelsea when they beat Manchester City 1-0 in the Champions League final in 2021. He also played for Spain 44 times.
Sevilla have lost their two opening games of La Liga and play at Girona on Sunday.