The 20-year-old joins from Bundesliga side TSG Hoffenheim for an undisclosed fee after impressing on the international stage.
Toure made three appearances for Ivory Coast at this summer’s FIFA World Cup, helping his country reach the knockout rounds.
He becomes the Magpies' second senior signing of the summer transfer window, following the arrival of French goalkeeper Ewen Jaouen.
"We're really pleased to have been able to bring Bazoumana to Newcastle United,” said Eddie Howe.
"He has shown his ability to perform in a top European league during his time in Germany and has gained really good experience with his national team, especially at this summer's World Cup.
"We feel that he’s a player with a really high ceiling - he's somebody who we believe can offer us something different. He also a lot of potential to unlock and we’re really looking forward to working with him."
Bazoumana Toure began his career at ASEC Mimosas before moving to Hammarby in 2024. His impressive form earned a transfer to Hoffenheim in 2025, where he scored five goals and provided nine assists last season.