Kayleigh Sinclair was their top performer, winning gold in the girls’ A one-metre final.
In the same competition, her team-mate Cody Powell-Tuckett finished fifth.
There were silver medals for Zachery Anderson and Aidan Heslop.
Anderson took second in the boys’ C/D platform final, while Heslop’s medal came in the boys’ B platform. Heslop’s team-mate Alfie Brown also reached the platform final, finishing sixth.
There was a bronze medal for Chrismon Clark in the girls’ B one-metre final.
Fellow Plymouth diver Alex Kostov reached both the boys’ A three-metre and one-metre finals, finishing fourth and fifth.
Summer Radcliffe (fourth) and Evanageline Piper (fifth) also reached the girls’ C three-metre final.
The top competition, which attracts divers from all over the country, continues until Sunday.