Four of the six events in the series involve out-of-Auckland travel, which is a bonus for the boys who always pack their surfboards so that they can also indulge their love of surfing.
All four are active members of their local Surf Life Saving NZ Clubs.
"Our first goal for the series is to have fun and participate," said Slessor White. "However, it's a completely different story on the surfboards."
He said each event in the nationwide series was a different challenge with its own character.
"The series is a network of people who all know each other - we all have some outside connection together, be it our school, our swimming club, surf lifesaving or other sports."
The event director for the State NZ Ocean Swim Series, Scott Rice, said it was great to see participants forming lasting friendships.
"This series is all about community and participation and it's fantastic that people of all ages are really embracing that."
Slessor-White, who also takes part in the weekly State Beach series, held in Takapuna, takes every opportunity to don his wetsuit.
"I love the ocean. Swimming serves me well for many things and I really enjoy the 5am training sessions."
He and his friends will be participating in the "I'm Going Long" distance at four of the events in the series. Other distances are the 200m "State OceanKids", the 300m "Give it a Go" and the 1000m "Step it Up".
The next swim in the series is the State Capital Classic on January 25. The event is held in Wellington and is the third of six events.
Youngsters who win their age group in the State OceanKids 200m event - for children aged 6 to 10 - are eligible to join the Jetstar Super Swim Squad.
This involves attending an end of season training camp in Auckland in April with some top name elite swimmers and coaches, with airfares and accommodation provided by Jetstar for children and a caregiver.
The other three events in the State New Zealand Ocean Swim Series are the State La Grande at Akaroa, the Sand to Surf at Mount Maunganui and the King of the Bays on Auckland's North Shore. The series runs from November to April.
Ocean Swim Series
1. Capital Classic (Wellington) Sunday January 25
2. La Grande (Akaroa) Sunday February 15
3. Sand to Surf (Mount Maunganui) Saturday March 21
4. King of the Bays (Auckland) Saturday April 18
For more information or to register visit www.oceanswim.co.nz