Tributes poured in on Friday for Marcio Freire after the legendary Brazilian died while surfing the giant waves at Nazare in Portugal.

Freire was among three pioneering Brazilian surfers who featured in the 2016 documentary "Mad Dogs" about their attempt to conquer the giant "Jaws" wave in Hawaii.

He was killed Thursday while surfing the celebrated Atlantic waves in Portugal, home of the "Nazare Canyon", rated one of the sport's biggest and most terrifying challenges.

"A 47-year-old man of Brazilian nationality died this afternoon after falling while practising surfing in Praia do Norte," Portugal's National Maritime Authority said in a statement.

"The rescuers found that the victim was in cardio-respiratory arrest, immediately starting resuscitation manoeuvres on the sand.

"After several attempts, it was not possible to reverse the situation."

Local sources told AFP the victim was the veteran surfer Freire, who had lived for 20 years in Hawaii, the sport's traditional homeland.

The sources also said that sea conditions were not particularly dangerous on Thursday.

Big-wave professional surfer Nic von Rupp led the tributes on social media.

"Today we lost one of ours," he wrote on Instagram.

"Always had loads of respect for Marcio as one of the paddle pioneers at jaws. Today I saw him surf all day in Nazare with a huge smile.

"With that huge smile is how I'm going to remember him."

Also posting on Instagram from Nazare, Freire's fellow Brazilian surfer Thiago Jacare paid tribute to a close friend he called "more than an idol" and "a true hero".

Nazare is where German surfer Sebastian Steudtner set the world record for the biggest wave ever surfed -- an 86ft (26.2m) breaker -- on October 29, 2020.

Several accidents have occurred at the spot since American Garrett McNamara introduced it to the giant wave surfing community in the early 2010s.

However, none had been fatal until Thursday.