Leicester City, both Premier League sides said on Wednesday, with the Frenchman signing a seven-year contract with the west London club.
Financial details were not disclosed but British media reports said the deal was worth 70 million pounds ($81.33 million). "Wesley is a hugely promising defender who has already proven his quality in the Premier League at a young age," Chelsea chairman Todd Boehly said. "We are delighted we were able to bring one of Europe's most exciting talents to Chelsea and further strengthen that area of our squad, both for this season and many more to come." The 21-year-old had made the switch to the Premier League in October 2020, joining from Ligue 1 side St Etienne for a reported fee of up to 36.5 million pounds.
During his two seasons at Leicester, he made 52 appearances in all competitions, including 37 in the league and 11 across two European campaigns.
In his debut 2020-21 season, he was named as the club's Young Player of the Year after helping Leicester win their first FA Cup, performing well in the final against Chelsea. "The two last days have been really big days for me and I'm very happy," Fofana told the club's website. "I trained this morning with the team and it's a dream for me.