Tabuai-Fidow came to the new NRL club from the Cowboys on a two-year deal and has been one of the most dangerous players in the competition in 2023.
The Dolphins have now upgraded 'The Hammer' and locked him in for an extra three seasons to secure their fullback berth for five years.
When Tabuai-Fidow moved to the Dolphins in November, he had just 50 matches of top-grade experience behind him and was recovering from a serious ankle injury suffered playing for Samoa at the Rugby League World Cup.
But the 21-year-old has been nothing short of inspirational under coach Wayne Bennett and has stamped himself as one of the competition's leading players.
Dolphins chief executive Terry Reader said the way Tabuai-Fidow had underlined his class on the field had been a key factor in brokering the long-term deal.
"It is so pleasing that Hamiso has shown the form we believed he was capable of and demonstrated just what a match winner he can be," said Reader.
"He came to the Dolphins on the chance to assert himself as a fullback - an opportunity we must sincerely thank the Cowboys for in allowing Hamiso a release to take up that challenge.
"There is no doubt that Hamiso has shown he is a true game breaker by scoring tries in each of his first six games for the club.
"That included our historic first ever premiership try against the Roosters in round one, a moment that will live in the memories of everyone who attended that game on that famous day.
"He has now established himself as one of the form fullbacks in the NRL and that is why he has got this reward."
Tabuai-Fidow has scored eight tries already this season for the Dolphins, and will aim to add to that tally when the new NRL club hosts the Gold Coast Titans in a south-east Queensland derby at Suncorp Stadium on Sunday.
The Dolphins are currently eighth on the ladder with four wins from seven matches.
7°C