Mauricio Abrunhosa, 48, was competing at Curl Curl beach this morning when a fellow rider spotted him in trouble.
He was pulled from the surf unconscious, and an off-duty nurse did CPR until NSW Ambulance paramedics arrived.
He was rushed to Royal North Shore Hospital but later died.
Known as Moz, Abrunhosa was a member of the Sydney Bodyboard Club and was a two time state champion in the sport.
Surf Life Saving duty officer Tracey Hare-Boyd said life savers didn’t know what happened.
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We are unsure if the bodyboarder actually fell ogf his board and hit his head or of it was a medical episode,” she said.
Friends are paying tribute to Abrunhosa.
“I think the whole community feels quite deep and sad because it could be any of us I guess,” one friend said.
NSW Police said a report would be prepared for the information of the coroner.