Cronulla will be with forward pack gun Caitlan Johnston from 2025 after signing the 23-year-old to a three-year deal this week.

The Awabakal and Gamilaroi woman has a final year remaining at her current club Newcatle Knights before moving south to join the competition newcomers, who finished sixth in their debut season last year.

A NSW and Indigenous All Stars representative and 2022 World Cup winner, Johnston lifted her second NRLW trophy with Newcastle as an inaugural signing and previous captain for the Novacastrians after starting her career at the Roosters.

New Knights coach and Gomeroi man Ronald Griffiths said it was "disappointing" to lose a local talent in Johnston, but that the prop has assured "she's going to play every part she can to make sure we go three-peat".

"That decision was made recently (to leave the Knights)" he told the Newcastle Herald.

"I understand it's a business decision from her end...it's obviously disappointing being home-grown, but I do respect her decision and she knows that personally.

"She's assured me that for 2024, she's red and blue through and through, and then after that she'll move on to her next chapter."

The Sharks are celebrating their "coup" of one of the competition's elite.

"This is a significant coup for our club given Caitlan has firmly established herself as one of the premier forwards in the NRLW and a terrific leader," Cronulla-Sutherland coach Tony Herman said.

"She's already scaled the heights of the game, but at 23, her best years are still ahead of her. We look forward to her coming on board in 2025 and sharing her experience."

Johnston debuted as an 18 year old for the Roosters before going on to play 18 first grade games for 15 wins and back-to-back premierships at Newcastle between 2021-2023.

The NRWL season kicks off when the Knights meet the Roosters on July 27.