Of the place-getters in the event's 10 categories, five were participants from Arrowtown.
Joseph Swale's individual time of 22min 24sec put him in third place of the year 5 and 6 boys competition, while Sophie Aitken placed second in the girls equivalent category with a time of 24min 21sec.
Also from Arrowtown were members of the winning year 5 and 6 boys team, which recorded 18min 43sec, as well as those in the winning year 7 and 8 mixed team with 30min 50sec.
Finn Bilous, of Hawea Flat School, won the individual year 5 and 6 boys competition in a time of 20min 59sec, while Queenstown Primary School pupil Sienna Strachan won the girls event with a time of 24min 17sec.
Wanaka Primary School pupils won the year 5 and 6 girls team event with 23min 52sec, and Goldfields Primary School won the mixed team age equivalent with 23min 01sec.
In the year 7 and 8 boys individual section Hamish McKay, of The Terrace Primary School, won in 30min 37sec, and Emma Patton, of Cromwell College, in 34min 28sec, took the girls' title.
A Queenstown Primary School team won the year 7 and 8 boys category in 32min 02sec, while the girls team in that age group was just four seconds behind the boys and was won by pupils from Mount Aspiring College in 32min 06sec.
Triathlon organiser Bill Godsall, of Sport Central, said about 640 primary school-aged pupils took part, in either team or individual events, from 24 schools from throughout Central Otago, Queenstown, Wanaka, and Arrowtown.
The year 5 and 6 competition comprised a 1.5km run, 5km cycle, and 100m swim, while year 6 and 7 pupils completed a 3km run, 10km cycle, and 150m swim.
Mr Godsall said the annual triathlon had been held in Cromwell for about the past 10 years.