Jack Musika, representing Coogee Beach Surf Life Saving Club, claimed the win in the under-14 male beach flags division.
A day earlier he had claimed silver in the under-14 beach sprints.
Musika said he was nervous ahead of his first race.
�There were top-level performers there and I just wanted to perform well,� he said.
�I went over wanting to make the finals but I didn�t expect to medal.�
Musika said the competition was tight.
The judges were tough on anyone breaking at the start and with no second chances, there were plenty of disappointed athletes.
�I didn�t really know how good everyone else was or where I�d fit in with them,� he said.
�But after the first race I was a lot calmer.
�I was really happy to win the medals.�
Coogee Beach SLSC surf sports director Darren Spencer said the medals were a reward for effort.
�There�s a lot of natural ability there but he�s a good kid, quiet, modest and always competes hard,� he said.
�He�s at that age where a lot of the boys drop out so hopefully he can continue on because he�s a good role model for our club.�
Fellow club mate Wesley Muller, who competed in the Masters division, completed the two-man contingent from Coogee tackling the largest annual event of its kind in the world.
Muller claimed bronze in the 2km beach run for men aged 35-39.
In total more than 7000 competitors from 311 Australian surf life saving clubs flooded North Kirra Beach to compete in the event�s centenary year.