Cousins was not offered a new deal by the Hawks for next season as the club continues its list rebuild under incoming senior coach Sam Mitchell, with a total of six players at Waverley cut this off-season.
The 23-year-old's departure from Hawthorn raised some eyebrows given his value to Mitchell's youthful list, having averaged near 19 disposals, four tackles and four inside 50s from his 10 appearances in 2021.
Despite nominating for this week's National Draft, Cousins is now tipped to link up with the Seagulls for next season, according to Leader reporter Paul Amy.
The Mansfield product will bring 35 games of AFL experience from his five seasons in the brown and gold, with his midfield capabilities set to be a major boost for Justin Plapp's side.
Locked in: James Cousins at Williamstown. The former Hawk was courted by a few clubs and will be one of the recruits of the 2022 VFL season.
— Paul Amy (@PaulAmy375) November 24, 2021
Williamstown finished their 2021 season with six wins from their nine matches, also recording a draw against Richmond to finish the cut-short campaign seventh on the ladder.
The AFL announced a string of rule changes for the VFL in 2022, while the fixture will see all 21 clubs play 18 matches across 22 rounds.
The salary cap has also been increased to $220,000 from $200,000 for standalone clubs and $110,000 from $100,000 for AFL and aligned clubs.