And then out of the blue he got a call one day asking him to be the Kiwi representative in the Ultimate Waterman. He said yes, but it took him a bit of time to consider whether he was going to aim to win or just make up the numbers and enjoy the ride.
"The organisers felt that I had the credentials to take on all these other athletes, but I think everybody thought it was going to take a huge effort on my part," Kereopa says.
"When I got the invitation, I did think - am I going to say yes because I want to win? And what came to mind was, yes, I want to compete for the title."
Kereopa trained hard over the summer to get himself into shape. He says he felt in top condition by the time day one rolled around, but the reality of what he was up against hit home immediately.
"I had to deal with the amazing profiles these guys brought and the personal sponsorships they had. I had to block all that out and just believe in the hard work I had put in."
The inequality was acute. "All the lessons I did in my surf school paid for the surf boards I had. And then I watched all these guys pull out all the boards they got for free," he laughs.
But a disparity in resources wasn't the only obstacle. There was also the small matter of the athletes themselves, who were nothing short of world class.
"The first event was the waka ama race. Danny Ching [from the United States] and Georges Cronsteadt [of Tahiti] were pretty much the best guys in that discipline, so first and second were already taken. It was a battle for third and fourth."
The field then moved to Whitianga for the short board surfing event, but a miscommunication saw Kereopa's best boards sent down to Otago, where the next event was to be held.
"I was riding a fourth choice board and I was pretty mad because short boarding is one of my favourite events."
Kereopa finished fourth again, and it looked like his improbable hunt for the title was over.
But things turned around in the stand-up paddle board surfing on the Otago coast, where he went head to head with the world champion Lenny and came out on top.
"Beating Kai was an amazing feeling," he says. "I was stoked. In the last five minutes I picked off a wave and got a 10-point ride. That's what made me win - I held on and kept the faith."
History then repeated in the long board event in Raglan, Kereopa's hometown.
"We hit the final and Kai was in there. He was leading right into the last five minutes and I needed another big score. I got a nine-plus ride and pushed him back into second. After that I was leading the whole event."
Things came to a head at Mission Bay for the final event of the competition, the gruelling 15km stand-up paddle board endurance race. Kereopa knew he had no chance of winning the event, but all he had to do was make sure Lenny didn't finish too far above him. If he could manage that, he would take the crown.
"I was overwhelmed by how much support there was for me on the beach, but I still had to get through the race.
"I paddled the hardest I've paddled in a long time just to stay with Kai, and as it turned out I finished right behind him. I took the title."
The result has the potential to be life changing for Kereopa.
"There's going to be some amazing opportunities coming from this event. It's going to take a financial sponsor - a good, loyal corporate. I worked hard to get all the best gear under my feet and I'm super fit," he says.
"My partner Renee and I are sitting down to evaluate what will fit best for our future plans. I'd like to win the world paddle board championships, which is in Mexico in a few months time.
"If I can get the financial backing to get on the stand-up paddle board world tour I can seriously compete against the world."
What: The Ultimate Waterman
Winner: Daniel Kereopa of Raglan beat an international field.
For more information, visit: http://www.theultimatewaterman.com/
