Swimming in the Baywave Aquatic Centre pool is different from their usual makeshift 50m ocean facility at a naval base back home in Tonga.
But that doesn't faze the pair. "We are here to win," Alan says.
Vaoahi and Alan are part of Tonga's Ocean of Light Academy team dubbed Pool Runnings after the 1988 Winter Olympics Jamaican bobsleigh team that inspired the film Cool Runnings.
The team, including fellow teammates Saia Day and Keli Langi, made headlines at last year's AIMS Games after being awarded the ACC Sport Smart medal for the most spirited, fair-playing and respectful team.
Coach Tina Uhi said only half of the team had returned this year after financial constraints meant one member could not make the trip and the other was too old to compete.
But Vaoahi and Alan are making their mark at the 16th annual AIMS Games in Tauranga even without their full team.
The teenagers both made the finals this week.
Alan won gold in the 100m butterfly with a time of 1m06s72. He also placed second in the 50m breaststroke (34s09), 50m butterfly (28s53) and 50m backstroke (30s54).
Vaoahi finished ninth in the 200m breaststroke (3m10s04) and tied seventh in the 50m breaststroke (39s12).
Fellow Tonga swimmer, Mana Taufa, from Tonga Side School finished with personal bests on his two events in the 50m butterfly and breaststroke.
Vaoahi and Alan say they are inspired by their idol American swimmer and Olympic champion Michael Phelps.
"I want to become an Olympic swimmer one day," Vaoahi said.
Vaoahi's mum Suliana Afu said she was proud of how far the pair had come.
Afu said they did not have access to the same training facilities and professional coaches as in New Zealand.
"We are so proud of them."
The team trains in a makeshift ocean pool at a naval base in Tonga where they have to ask permission to train.
Suliana said the teenagers had volunteer coaches who taught them how to swim from YouTube videos.
"Every competition is an opportunity for them to learn and further their swimming skills," she said.
"We understand that they love swimming. But we tell them to just to do their best because they are here not only to represent their school but to represent their country."
Coach Tina Uhi said competing in New Zealand helped the swimmers to improve and learn from professional coaches they could not afford or have back home.
"We can see the more competition they attend it is improving their time and they get good personal bests.
"We learn from the different culture."
Vaoahi and Alan trained with the United Swim Club in Auckland a week before the AIMS Games started.
"We want to say thank you to the Polianski family, coaches and also coach Alexander Graudins helping with the techniques of our swimmers and also with their training preparations," Uhi said.
Tournament director Vicki Semple invited the swimmers to the games after meeting them while filming an item on the Tongan badminton team coming to AIMS in Tonga last year.
"To see what they've achieved since is utterly inspirational and I hope the awareness they're raising within the sport and internationally can one day let them get their own pool."