Hamiso Tabuai-Fidow scored 14 tries, set up 12 more and broke 89 tackles in 21 appearances for the Dolphins in 2026.
The 25-year-old has agreed to a long-term extension, with the club securing him before he could negotiate with rival teams from November 1.
He was previously contracted through the 2027 season. The Daily Telegraph reported that the new agreement is understood to be long-term.
Tabuai-Fidow joined the Dolphins from the North Queensland Cowboys ahead of the club's inaugural 2023 season.
Primarily a fullback, he can also play across the backline and has become a key attacking player.
The Dolphins have also retained outside back Selwyn Cobbo, who signed in September through to the end of the 2031 season.
Herbie Farnworth and Jack Bostock remain off-contract at the end of 2027, leaving the club with more backline decisions to make.
Farnworth has been linked with the Sydney Roosters, while Bostock has attracted interest from his former junior club, the St George Illawarra Dragons.
Tabuai-Fidow's extension gives the Dolphins greater certainty as they seek to keep their established outside backs from rival clubs.