Kite foil sailor J.J. Rice, who was to represent Tonga at the Paris Olympics, has died in a diving accident. He was 18.

Rice's father Darren Rice confirmed his son's death to the Matangi Tonga newspaper.

Jackson James Rice was to be the first caucasian to represent Tonga at an Olympic Games.

His death occurred on Saturday at Faleloa, on the island of Ha'apai in the Tonga archipelago.

He was free diving from a boat when he suffered a suspected shallow water blackout, Matangi Tonga reported. Efforts to revive him were unsuccessful.

"I was blessed with the most amazing brother in the whole world and it pains me to say that he's passed away," Rice's sister Lily said in a Facebook post.

"He was an amazing kitefoiler and he would have made it to the Olympics and come out with a big shiny medal. He made so many amazing friends all over the world."

Rice was born in the US to British-born parents but grew up on Ha'apai where his parents operate a tourist lodge.

He finished eighth at the Sail Sydney event in December to earn his Olympic place. Kite-foiling will be an Olympic sport for the first time in Paris.

Rice recently had been training and competing in Europe.