PJ celebrated his 13th birthday on the day, and took part with his father and brother as part of the largest school team entered in the iconic event.

PJ, his father James and brother Zachary (9) were part of a team of 67 from The Armidale School in northern NSW, where PJ is a boarder.

The trio loved the atmosphere of the event, which they completed in one hour, 40 minutes and 44 seconds.

"It was really good, I got to be in it with my family and saw Mum at the end, which was an extra special birthday present," PJ said.

The schoolmates from Armidale made the 1000km return trip by bus to participate.

"There was music everywhere, plenty of drinks stations, it was just a great atmosphere. I'll definitely do it again."

The Armidale School athletics co-ordinator Jim Pennington said PJ was the first Year 7 boy to complete the event that had only grown in popularity.

"Part of this is because the City to Surf now forms part of a school award called the TAS Triple Crown, for those students who complete it, the 2km Coffs Harbour Ocean Swim and the 111km overnight Hawkesbury Canoe Classic during their time at the school," he said.

"Earlier this year PJ and his father also rode in the 240km Tour de Rocks charity cycle classic from Armidale to South West Rocks, so he is clearly a young man with a strong sense of adventure and commitment and is to be congratulated on his efforts," Mr Pennington said.