While he has dominated longboarding's junior ranks for the past two years, Guthrie mixes it up outside competition with high-energy shortboard surfing.
He has only just left junior competition behind but Sam Guthrie has all the momentum of a 9-foot Malibu board in perfect trim.
With the summer's Hyundai Pro longboard tour schedule announced recently, the Mount teenager has consecutive junior titles and overall fifth in the open division last year tucked into his boardshorts' wax pocket.
Factor in back-to-back victories in his final four junior tour events for 2009 and Guthrie looks a strong bet to shake up the country's top order of longboard aficionados.
"It's been pretty amazing this year, it was easily the best year of competition I've had," said 18-year-old Guthrie.
"Now it's time to step it up. I've been noticed by Hyundai, it's a good opportunity. They've realised how much talent there is in New Zealand longboarding and I definitely think they want to produce world-class surfers here."
With school out for good - he finished at Mount College last week with NCEA Level 3 - Guthrie is happy to keep career options open for now and enjoy a summer in and around the waves. Work on the local beaches as a volunteer lifeguard over the next few months will ensure he stays fit for the tour, which gets under way in his Mount home waters on January 2-3.
Also beckoning is the Association of Surfing Professionals' Australian longboard tour, the next logical step if the young goofy-footer wants to launch into international competition.
With 2009 nationals champ and tour runner-up Dan Proctor, who is Guthrie's pick as the man to beat this year, gearing up to test the waters across the Tasman, Guthrie will be watching closely.
"You have to do extremely well over there to go on to the ASP world longboard tour, which would be the ultimate," he said.
Understated by nature, when pressed on his own chances of cracking it in Australia, Guthrie's core confidence surfaces: "I reckon I can make it."
There's been another change for the lad who began surfing at 6 in front of his family's Oceanbeach Rd home, helped by dad Richard and mum Fiona. The family's recent shift to the Main Beach area means the wider Mount crew will get to see the fleet-footed teen in action more regularly ... when the summer swells finally start to roll in, that is.
"Yeah, it's been really small, but I've snuck in a few waves. While there's been no surf, I've got right into triathlon."
With results like a second placing in under-19 at this year's Monty's Revenge at Whakatane, Guthrie admits: "I'm pretty competitive, it [triathlon] keeps me going."
On the water, he's helped out by long-time sponsor Bear Surfboards, tapping into the shaping expertise of Raglan's Mike Thomson.
Once the tour wraps up with the final event at Port Waikato in March, Guthrie will put wave-riding on the back-burner. In the middle of next year, he'll spend a three months with Camp America.
"I'm really looking forward to travelling ... in years to come I'll have a closer look at a career in or around surfing, but I don't want to rely on it."
While he discovered a natural flair when first riding longboards about seven years ago, Guthrie still loves tearing it up on a contemporary shortboard whenever conditions allow. "I don't want to be out there nabbing all the waves on my big board, my mates would hate me," he laughs.
At least two other Mount locals will be footing it on this summer's tour.
Having focused on work commitments last year, Ant McColl is looking forward to hitting all five competitions and welcomes the move of the sole South Island contest from Christchurch to Dunedin.
"The surf at Christchurch was mostly pretty average and they have so much wicked surf around Dunedin. I'm amping to get down there," 22-year-old McColl says.
The ever-competitive Owen Barnes is set to trade his customary shortboard attack for a tilt at the four North Island events. Finishing seventh last year after tackling four of the six tour events, Barnes, 35, is a perennial threat on any equipment.