Engels becomes West Ham’s fourth signing of the summer, following Venezuela midfielder Keiber Lamadrid, Dutch defender Joel Veltman and Israel winger Manor Solomon.
West Ham’s director of player recruitment, Nils Koppen, told the club website they had tracked Arne for a considerable period and viewed him as a priority target.
He said that, despite Engels’ youth, he already boasts strong experience, has proven himself at a major club and consistently displays assurance in his performances.
Koppen added that Engels possesses the right qualities on and off the pitch to fit the club’s long-term plan, and that the player is highly motivated to take on the challenge.
Capped four times by Belgium, Engels won back-to-back Scottish Premiership titles with Celtic after joining from Augsburg in August 2024, having begun his career at Club Brugge.
Engels described the move as an exciting project, with the primary aim of returning to the Premier League. He said his focus is on helping the team and, with the supporters, securing as many wins as possible.
He added that he hopes it will be a successful year.