The 38-year-old retired in 2017 after a successful career that also saw him play for Everton and Manchester City.
Following his move to City in 2009, he won two Premier League titles, the FA Cup and League Cup before leaving for The Hawthorns in 2014.
In a statement on their Twitter page, Racing said Lescott will play in their Copa del Rey first-round clash with top-flight side Levante on December 16. The statement read: “Our president Morris Pagniello and Racing Murcia are happy to announce the signing of English star Joleon Lescott, who will play in our Copa del Rey fixture against Levante.”
Lescott made more than 600 professional appearances in his career, including 26 England caps.