The 20-year-old, who operates as either a striker or midfielder, impressed for the Sky Blues, scoring nine times in 36 senior appearances for them and his performances caught the eye of Foxes boss Craig Shakespeare.
Thomas has signed a three-year deal and the Leicester-born youngster, who is likely to feature for the Under-23s to begin with, is raring to go - with his ambition to become a first-teamer as soon as possible.
"The facilities are unbelievable and I just can't wait to get started," he told LCFC TV. "It's my hometown, I only live 10-15 minutes away in Wigston. It's always good to play for your hometown team so hopefully I can push on from here.
"I've played 50 odd games at professional level so maybe I have got that head start over other 20-year-olds in the country,” he added. "Hopefully I can use that experience to get into the first team here.
"The aim is to play first team football and try and help the Club. That's the aim, to try and hit the ground running."