Korbin Sims will play for St George Illawarra Dragons next season after agreeing to leave NRL rivals the Brisbane Broncos.

Sims has signed a three-year deal with the Dragons which will keep the front-rower at the club until at least the end of the 2021 campaign.

The 26-year-old – who has amassed 112 NRL appearances – will link up with brother Tariq Sims at the Dragons in 2019.

"Korbin has some really good years in front of him. We believe he is coming into his prime, and he brings us some stability and experience as well as being a really good replacement for Leeson moving forward," director of rugby league pathways and list management Ian Millward said.

"The club spoke to [Broncos coach] Wayne Bennett about Korbin, and he gave him a big rap as a person and coachable-wise, and where he sees him developing moving forward. We're really pleased to get him on board.

"We have some really good emerging forwards that Korbin will help in their development too, like Luciano Leilua, Jacob Host, Josh Kerr, Jackson Ford, Reece Robson and the like.

"We know how close Korbin was to playing for Queensland, and he's seen the advancement of [brother] Tariq to play Origin this season as well as Jack de Belin, Paul Vaughan and Tyson Frizell so we know he's keen to follow in their footsteps."

The Dragons are third in the NRL this season, two points adrift of leaders the South Sydney Rabbitohs.