The Northland contingent's speciality is the street division, which involves skateboard-like tricks such as spins, flips and jumps.
Jenny Huriwai, Chris' mother and the manager of Circus Kumarani, said the young Northlanders' success was the result of years of hard work.
"They're really dedicated. They were winners before they went over there for what they'd achieved. I know I should say I'm really proud of my son, but I was proud of him before. I'm really proud of how he's become a role model for other kids."
Mrs Huriwai said it was Sam who first brought her son and Circus Kumarani together, by inviting him to a circus workshop at Kai Iwi Lakes shortly after he won his first world title.
She was already riding then but meeting Chris encouraged her to get into the more extreme end of the sport.
Mrs Huriwai heard the news via Facebook and Samuel's mother in Italy. She was planning a street party in Dargaville when the trio returned; a welcome is also being organised in Kaikohe.
Samuel's father, George Tzikoucos of Kaikohe, said he was immensely proud. "I'm pretty rapt. He's done extremely well and can only get better. They've all come up against some really tough competition and come home champions."
A few days earlier Sam and Samuel had both placed fourth in their sections of the flatland event, although it is not their strength.