The Dolphins have also retained Selwyn Cobbo and Kulikefu Finefeuiaki.
Fullback Hamiso Tabuai-Fidow has signed a two-year extension through the end of 2029, keeping him at the club for at least three more seasons.
His salary is believed to rise to about $1.4 million annually, potentially complicating efforts to retain outside backs Jack Bostock and Herbie Farnworth.
Bostock is reportedly interested in returning to Sydney, where St George Illawarra leads the race; Farnworth has been linked with the Sydney Roosters for months.
CEO Terry Reader described the retention as one of the biggest wins in club history.
Reader said: "He is a player who can change a game in an instant, and his record of 66 tries in Dolphins colours speaks for itself."
Second-rower Connelly Lemuelu is understood to be close to joining them, while Thomas Flegler has yet to decide and could leave.