The Australian team dominated the final day of the event, picking up six of the 12 titles on offer as well as comprehensively winning the tag team event after being led by an outstanding performance from Simpson.
It was Simpson’s first title after having come up short in three previous finals over the past decade.
"I have been standing up here three times previously, claiming the runner-up finish and coming up just short. So this title feels like it has been a long time coming," he said.
It was the tightest final of the day with Simpson surfing to a modest 9.50-point heat total in the final. American surfer Sam Coyne finished with a 9.43-point heat total.
"It wasn’t the way I wanted to win and I am sorry for having to play out the last few minutes like that Sam, but it had to be done," added Simpson, who "dropped anchor’’ for the final five minutes, holding priority and preventing Coyne from catching any good wave.
Coyne had a final shot at the title but came up short after he fell on his second turn on a wave with minutes to go, the wave certainly having the chance to flip the final on its head.
The final day of the event had clean waves in the 1m range, with light offshore winds. However it was the full tide that hampered wave quality in the finals, pushing the participants’ small wave surfing capabilities.
Earlier in the day Simpson eliminated Albert Munoz in the first semifinal while Coyne eliminated Baden Smith, of Australia, in the second semifinal.
Australia claimed five further titles which went to Albert Munoz in the 40-44 age bracket, Paul O’Neill in the 55-59 age bracket, Wayne Jennings in the 60-65 age bracket and Noah Bateup and Owen Fairweather in the 17-20s and Under 16 age group respectively.
South Africa claimed two titles on the final day, Jedd McNeilage winning the over 30-39 age bracket and Gigs Celliers winning the 50-55 age bracket.
United States and Tahiti took one title each, Shaun Murphy winning the 20-29 age bracket and Phillipe Klima winning the over-65 age bracket.
Host New Zealand claimed two titles on the final day, Jason Revis winning the 45-49 bracket and Julia Phillips winning the women’s division.
