Young gun prop Sebastian Su'a will leave the Newcastle Knights at the end of the 2025 NRL season, with the Dolphins confirming he has signed a two-year deal with the club.

Already an NRL debutant, the 21-year-old has risen through the Knights' development system in recent years and will now add to the selection headaches at the Dolphins, who have a host of young forwards on their books already.

It's not hard to see why the NRL's 17th club, who joined the competition ahead of the 2024 season, wanted to sign Su'a though.

"Our assistant coach Rory Kostjasyn knows Sebastian from his time at the Knights, and we believe he will have a really good opportunity to make an impact here," Dolphins CEO Terry Reader said in a statement on Su'a's signing.

"Having someone of that size, learning from the experience of our existing pack, makes Seb an exciting prospect for us."

He stands at 198 centimetres, has uncoachable attributes and plenty of upside which will only serve to add to Kristian Woolf's squad who are aiming to make the top eight for the first time in 2025.

As it stands, the Dolphins are yet to make decisions on the contracts of other forwards Kenneath Bromwich, Felise Kaufusi, Josh Kerr, Mark Nicholls, Mason Teague and Michael Waqa, who promotes to the club's Top 30 for the first time in 2025. The group of six are all off-contract at the end of 2025.

Su'a's signing could well leave at least one of them heading for the Redcliffe exit gates, although that said, there is no guarantee any of Kaufusi, Bromwich or Nicholls continue their careers into 2026, with Wayne Bennett's original strategy of signing experienced forwards urgently needing a refresh now under Woolf's leadership.

Su'a is the first of those to arrive in 2026, following the acquisitions of Kulikefu Finefeuiaki from the North Queensland Cowboys, and Daniel Saifiti from the Knights for the 2025 campaign.

His father, Murphy Su'a, represented New Zealand in Test cricket, and Sebastian also played rugby union as a junior during his time in New Zealand before making the switch to Australia and rugby league on a full-time basis.

The youngster is heading into his fourth season with the Knights, having impressed at each level he has played.

Su'a will join the Dolphins for pre-season training in November.