More than 700 competitors aged from eight to 60 took part in the event at the John Charles Centre for Sport.
And Mount Kelly and Plymouth College both returned home with a medal each.
Mount Kelly Foundation’s Matilda Purnell claimed the under-11 girls’ title in the event, which sees athletes compete in the swimming and running disciplines of modern pentathlon. She scored 2.732 points to win by an impressive 63 points.
There was a bronze medal for Plymouth College’s Chloe Olford in the under-19 girls’ category. She scored 2,196 points to finish behind Twynham’s Abigail Richardson and Queen Elizabeth School’s Emma Whitaker.
There was also top seven finishes for Plymouth College’s Tomas Maksimovic in the under-19 boys’ event and Fynn Baker in the under-11 boys’ competition.
Scott Oliver, Lomorna Cox, Daisy Holdsworth, Rory Cox and Billy Simpson also represented Plymouth College at the event, while Olivia Purnell, Caoimhe Dolby, Annabelle Hess, Ellena Hess and Edward Sorensen competed for Mount Kelly.
All competitors had to qualify for the championships via 21 preliminary competitions held around the country earlier in the year.