Ohope's Jared Gebert, Caleb Cutmore (Raglan), Elliot Brown (Dunedin), Tegen Bishop (Christchurch) and Saffi Vette (Gisborne) make up the rest of the Kiwi squad.
Teachers Kahn Butler (coach, Mount Maunganui College) and Damian Galvan (manager, Tauranga Boys' College) round out the Western Bay's influence.
Galvan said the below-average surf conditions along the Bay of Plenty coast helped to produce high quality, technically proficient surfers.
"Over the last 10 years we have had a number of kids from here make this team and it has always been the small wave surfers being able to grovel around in this rubbish surf, making them technically sound," he said.
"Then you go to the nicer waves at Piha, Gisborne and Raglan and suddenly these technical kids do all right. Also, I think there is a strong push here. At Mount College they have a very strong team and we have had a good team at Boys' College and Otumoetai has had some good surfers.
"It is just this family on the beach culture and that is why we have such a good run at the moment."
New Zealand's best performance at the world juniors was last year when they finished 10th.
Butler, 17, New Zealand's first Red Bull surf athlete who scored his maiden victory on the Australian Pro Junior series earlier this year, will move up to the under-18 division and has a podium finish in mind.
"I believe the team can go higher this year. I am stoked to have so many Mounties in the team. Everyone's listening and really focused and ready to go," he said.
"Conditions in Japan could be real small and real gutless like the last time we went over, so we just have to be prepared for that. That is why we are training here (Omanu) on these junky waves so by the time we get there we are all used to these conditions."
Elin Tawharu, 16, who secured New Zealand's first medal in a decade placing third in the Under-16 division at the 2016 event in Portugal, will be one to watch as she steps up to the under-18 division.