Matt Healy, Zanda Siziba and Cameron Stewart have signed their first pro deals with the Blues.
Midfielder Healy, who featured for the U23s last season, joined the Blues as a scholar in 2018 having previously been with College Corinthians.
The 19-year-old, who won Republic of Ireland caps at U15 and U16 levels, has penned a one-year deal with the club having an option for a further season.
Siziba, who was previously with the youth set-ups at Dagenham & Redbridge and Tottenham, is another midfielder, who made his senior debut as a sub in the Papa John’s Trophy tie with Gillingham and his first start at Crawley in the same competition.
The 17-year-old, who qualifies to play international football for Zimbabwe, has signed a two-year deal with the club having an option for an additional campaign.
Centre-half Stewart, 18, joined the Blues from Linfield in the summer of 2019 when he agreed a three-year scholarship and the one-year pro deal he has signed today.
The Ballymena-born defender won caps with Northern Ireland at U17 level.
Last month, fellow academy graduates Albie Armin, Cameron Humphreys and Ola Bello also signed their first pro deals.