The youngsters flocked to Queenstown's historic 43m Kawarau Bridge for celebrations, which included free jumps.
Pupils from Queenstown Primary, Wakatipu High School and Cromwell's Dunstan Primary were joined by teachers, spectators and bungy employees to celebrate the adventure tourism milestone.
Caped adventure hero Bungy Man led the countdowns and about 15 randomly selected pupils aged between 10 and 13 took the plunge, along with three teachers.
Bungy New Zealand chief executive Michelle Trapski said she was delighted with how the day had gone.
"Today was the perfect way to celebrate our 21st birthday.
"We did something similar for our 20th and it was so successful we thought we'd make it a regular event on the calendar.
"The kids have just been bouncing off the walls with excitement and we're delighted to give students from the Queenstown Lakes district, and some of their teachers and parents, the chance to jump as a rite of passage."
