The boys, aged 13, 15, and 16, are among those charged with possession of a Class A drug with intent to supply.
Fifteen people have been remanded in custody and are due to appear in court on Thursday.
Gwent Police raided 35 addresses in the city and made 25 arrests. Three people have been released with no charge and two are awaiting questioning.
Twenty people, including three teenage boys, have been charged following a drugs raid in Newport on Wednesday.