The celebrations began on Saturday with the under 13 years Gropers (boys) completing a stunning season to win a record-breaking four straight premierships in front of a parochial home ground crowd.

Not to be outdone on the Sunday, the under 14 years Marlins (girls) capped off a successful 2019 season with a hat-trick of grand final victories without losing a single match.

Coincidentally, both Bay teams are coached by police officers - the boys under the guidance of Clint Brown while the girls have former Olympian Matt Gray at the helm.

For Gray, who was assistant coach in the girls' first premiership in 2017 before taking over the full-time role for the past two season, the team's success has been a result of coordinated team work, friendship and communication.

"Sport is not just about physical fitness. It's about realising one's potential, learning to work together as a team, taking one's opportunities and most of all it's about enjoyment," Gray said.

"This year we had a squad of 20 girls, including seven new players getting their first taste of football, hailing from five different schools. The fact that they have been able to communicate and support each other is a credit to the girls' ability to be inclusive."

The weekend rain forced Sunday's decider against Wallsend to be moved to Feighan Oval at Warners Bay.

The Bay started the match strongly and led at every interval before holding off a strong finishing opposition and earn a thoroughly deserved 30-17 victory.

"It was a tough, low scoring game and the scores probably did not indicate how close the two teams were," Gray said.

"I am proud of the way they stuck to their task and showed enormous courage and resilience. Grand final victories are never easy to come by. This was a great team performance, ably led by captain Demi Bentley, while best on ground was Taylor Smith."

Competing in their first under 14 premiership after having won the under 12s for two consecutive seasons, most of the girls are expected to stay together for a second year in the under 14 junior competition.

Gray paid tribute to the AFL club's committee for providing a tremendous culture and environment for all juniors and manager Julie Lack.

Nelson Bay Junior AFL club spokesperson Penny Blyth said that the Marlins under 17 boys showed plenty of fight in their preliminary final loss to Newcastle from the previous weekend.

"Our boys took it to the minor premiers, but couldn't quite hold on. Newcastle won the final and followed up with a win over Terrigal on Sunday," she said.

"The Hunter AFL regional presentation was also conducted during the week with Marlins secretary Nicole Mulder named volunteer of the year, a most deserving honour.

"Other outstanding performances were recorded by Noah Connick (U/17s), who was placed third in the Hunter/Central Coast 'Best & Fairest', missing out by one vote for second, and Pat McGrath (U/13s), who was also placed third in the Hunter's 'Best and Fairest' votes."