His agency, Entourage Football, released a statement on its social media channels marking the young forward's switch to Sardinia.
"We are pleased to announce that Demi Akarakiri has officially signed his first professional contract with Cagliari Calcio," said the statement.
"After two years of excellent development at Everton, Demi is ready for a new challenge in Serie A.
"The way Cagliari develops young players in its first team makes their project very attractive."
The agency also thanked the player for his commitment throughout his development, adding: "Supporting you on your journey, watching you grow, working with you and your family, is a privilege. Congratulations, Demi, on this new adventure, we are all very proud of you."
Akarakiri, who is from London and turns 19 in September, spent ten years in Arsenal's Hale End academy before switching to Everton in the summer of 2024, joining on a scholarship deal alongside a batch of fellow academy prospects.
He made history early in his Everton career, becoming the first player to appear in a match at the club's new stadium during a youth friendly against Wigan Athletic, and went on to feature regularly for the Toffees' Under-18s and Under-21s, including in the Premier League International Cup.
Across his final season on Merseyside, Akarakiri made 33 appearances at Under-18 and Under-21 level, scoring three goals and adding two assists, form that convinced Cagliari officials to make repeated scouting trips to watch him play.
Everton had hoped to keep the midfielder beyond this summer and offered him fresh terms, but Akarakiri instead opted to join Cagliari as a free agent, signing a deal that runs to June 2030 — the maximum length permitted for a player of his age under Italian regulations — with the club holding an option to extend for a further three years.
The move fits a broader pattern at Cagliari, where head coach Fabio Pisacane has overseen a squad shaped around developing younger players alongside more experienced heads such as captain Alessandro Deiola.
Cagliari have been active in the transfer market this summer, with the club closing in on a permanent deal for forward Sebastiano Esposito from Inter Milan worth around €4million, following his loan spell in Sardinia last season.
The Sardinian club, who finished 15th in Serie A last season, are looking to build depth across their squad while continuing to blend academy pathways with shrewd market additions, with Akarakiri's arrival adding another young attacking option to Pisacane's options for the coming campaign.