South Australia's U18s Boys have taken out this year's National Championships, going undefeated in the carnival to win their first title since 2018.

The state side's championships opened with a strong win over the Allies before comfortable victories against Vic Metro, Western Australia and Vic Country, the latter securing the crown on Sunday at Marvel Stadium.

South Australia averaged 97.5 games across their perfect run, with their front third a dominant force as the three-pronged attack of Aidan Schubert, Mitch Marsh and Cameron Nairn caused havoc for defenders.

Marsh booted a current championships-high 12 goals in his four games, with a carnival-best five goals coming in their crown-clinching win over Vic Country.

Schubert, who kicked two goals in the final game, finished his championships with 10 goals, while Nairn booted nine - headlined by a seven-goal haul against WA.

Schubert and Nairn's Central Districts teammate Dyson Sharp took out the side's MVP Award with a dominant four-game run, averaging 26.5 disposals, 6.5 inside 50s, 5.0 tackles, 4.5 marks and 1.3 goals per game.

AFL Draft: SA forward's five goals help clinch U18s National Championships title
South Australia's Dyson Sharp wins the SA MVP Award at the 2025 U18s National Championships (Image: Zero Digital)

All four SA standouts have strengthened their bids as potential first-round draft selections, with Marsh looking to be one of the biggest risers from the start of the season as a 191cm forward with a good kick and strong marking.

South Australia had three top-five selections off the back of their last National Championships win, with Izak Rankine, Jack Lukosius and Connor Rozee all earning early selections.

Others to impress from the 2025 squad include wing pairing Harley Barker and Matt LeRay, Richmond father-son Louis Kellaway, North Adelaide's Sam Cumming, ruckman Sam Ainsworth and defender Jett Dahlitz.

South Australia were the first side to play all four games of their National Championships campaign, with no other side playing more than two games by the end of their run.

SYDNEY, AUSTRALIA - JUNE 01: Mitchell Marsh (R) of South Australia celebrates kicking a goal with saduring the Marsh AFL National Championships U18 Boys match between Allies and South Australia at Blacktown International Sportspark on June 01, 2025 in Sydney, Australia. (Photo by Jason McCawley/AFL Photos/via Getty Images)
SYDNEY, AUSTRALIA - JUNE 01: Mitchell Marsh (R) of South Australia celebrates kicking a goal with saduring the Marsh AFL National Championships U18 Boys match between Allies and South Australia at Blacktown International Sportspark on June 01, 2025 in Sydney, Australia. (Photo by Jason McCawley/AFL Photos/via Getty Images)

Vic Country, who are winless from their two matches, had some shining lights from their latest defeat, with forward Hugo Mikunda involved in 11 of their 17 scoring shots against South Australia.

Defender Josh Lindsay had a game-high 28 disposals, while utility Willem Duursma was strong on the last line.

Vic Country's next game is scheduled for Saturday against the Allies at Ikon Park.