The signature may surprise some, with Hiroti a backup option in the Sharks' system this year, scoring only five tries in his 13 starts.
Four of those appearances have been off the bench, while he hasn't made a single line break in any of his last five starts, including in wins over the last fortnight against the Canterbury Bulldogs and Brisbane Broncos.
Despite that, interim coach Josh Hannay has elected to retain the winger for this week's crucial clash with the Melbourne Storm, the Sharks likely to need a win to make the finals pending other results.
Incoming coach Craig Fitzgibbon has obviously seen enough though to offer the 22-year-old a new deal for his first year in charge.
Hiroti said he was looking forward to remaining at the club.
“I'm really happy to be at the Sharks again next year and to have my contract sorted ahead of such a big match this week,” Hiroti said.
“I’ve enjoyed working with Josh Hannay and the coaching staff this year but it is exciting to have the opportunity to learn from Craig Fitzgibbon and his assistant coaches next season to improve my game even further.
“We have a lot of really good young players here at the Sharks, plenty of experience in the squad as well and with the new signings there is a lot to look forward to next year."