The couple moved from Hereford in England to Pāpāmoa just over a year ago. It means they're around for important moments like this one.
They wouldn't have missed it.
"It's what you do," Jo said.
"Did I say we're very proud of him? It's worth repeating."
Asked if they too were talented sportspeople, Trevor said. "We were fit. We're down to croquet now but I played golf and tennis and hockey. Jo played hockey as well."
He said they'll be watching Finn compete from home on Sky Sport.
He's racing in the canoe slalom and sprint at the Buenos Aires 2018 Youth Olympic Games.
Jo and Trevor have watched their grandson grow and progress into a successful young athlete during their many trips to New Zealand over the past 25 years.
Now they live here permanently they can help out more – driving Finn and his younger brother (with kayaks on the roof) to trainings, for example.
Finn trains about 11 to 13 times a week.
Yesterday he said he was feeling some nerves and a bit of pressure, but was also excited and ready to compete.
The Tauranga Boys' College student was glad to have his grandparents there.
"It's good to have some support for a big event like this."
Trevor was confident in his grandson's ability.
"Finn is an exceptional sportsman, he's got a very cool head and I think he could do well. He could go all the way. Absolutely. He could bring a medal back."
Whether or not that happens, there's no question who will be waiting at the airport for him to arrive home.
*See Peter Williams, page 28