The 20-year-old Finnish player has agreed to a deal that will keep him with the team until 2027.
Tauriainen joined Chelsea in 2020 after moving from HJK.
His progress has been impressive, and he has been included in the first-team squad on several occasions.
In February 2024, he was named on the bench for the League Cup final match against Liverpool at Wembley Stadium.
He made his first-team debut in an FA Cup match against Leeds United at Stamford Bridge, coming on as a substitute.
Later in the season, he made his Premier League debut, replacing a player in the final minutes of a home match against Tottenham, marking another significant step in his development as a player.
