Students Camryn Moores, Charlie Potts and Lucas Doherty raced against 126 teams from private, independent and public schools from across the state.

The intermediate relay event for the 15 to 16 year-old boys involved a 600 metre swim, a 15km cycle and a 4km run.

Completing the course in a time of 42 minutes and 24 seconds Maitland High School teacher Nick Bower said the students were thrilled with the result.

He singled out Year 7 student Potts for his remarkable effort racing against students three and four years older.

While an accomplished pool swimmer this was the first time he had competed in an open water event, completing the swim leg in eighth position in a time of five minutes and 37 seconds.

"Charlie's a state level swimmer for his age so they approached Charlie to be in the team and he was pretty excited to say yes and to have a go with the big boys," Bower said.

"They were just looking for the fastest swimmer because they knew they were pretty quick with the run leg and the cycle leg and they just wanted to know who was going to be a good option for the swim leg.

"He had to pick that up on the go and then he had to do a bit of a sprint in the transition as well.

"The word on the street was he wasn't real keen on the 50 metre sprint he had to do when he got out of the water."

It was then on to Year 11 student Camryn Moores who rode the 15km cycle leg in a time of 25 minutes 57 seconds, getting the team up to fifth.

Bower said Moores is an accomplished cyclist who competes in events around the state and is also a skilled cross-country bike racer.

Fellow Year 11 student Lucas Doherty, who is also a talented Australian Rules footballer for the Maitland Saints, completed the 4km run leg in a lightning time of 10 minutes and 48 seconds to finish third overall.

The NSW All Schools Triathlon Championships were held for the first time in two years at the Sydney International Regatta Centre on February 23 and 24 featuring both individual and team events .

Maitland High School finished behind first placed Edmund Rice College from Wollongong with Picnic Point High School coming in second.