Thomas, 10, found a final push in the dying seconds of his heat to win the year 6 and below grade.
The George Street Normal School pupil was thrilled to win his first national title after a tough competition.
Running back ashore at Midway Beach, Thomas crossed his sister heading out to her final and the two embraced to celebrate his win.
Even though she was focused on her heat, seeing her brother succeed might have helped push Zara to victory.
The 12-year-old darted out to the water, looking for a strong performance after having "the best heat of my life" during the round robin surfs.
But the waves did not sit up for the Dunedin Normal Intermediate pupil, who had a fierce battle on her hands against Ahipara’s Jade Phillips.
"I was kind of stressing that whole heat because I hadn’t caught a wave, basically.
"Then I was so happy after I got that wave. I just saw my mum having her arms in the air and my whole family in the background having their arms up cheering."
Zara’s year 7 and 8 division title in Gisborne is her second national title, having won the under-14 accolade earlier this year.
She was rapt to win alongside her brother.
"I was so happy for him, but then it just sort of sank in after my heat as well."
Thomas also loved seeing his sister do well — he appreciated the support his family provided, passing on their tips and tricks.
"I just find it fun," Thomas said.
"You can make friends in the surf and you can just joke around a lot — it’s quite fun."
They do not have to look far for inspiration on the water.
Their eldest brother, Jake, 19, has previously placed second at the national championships, and brother Alexis, 16, has several national titles to his name.
Alexis has also represented New Zealand twice at the junior world surfing championships, including finishing fourth in El Salvador earlier this year.
They will compete at the national championships in Taranaki in January.
