Wigan Warriors back-rowers Liam Farrell and Joel Tomkins have signed five-year and two-year deals, while prop Taulima Tautai signed a three-year contract.
England international Farrell, 26, has won eight trophies with the Warriors in 196 appearances.
Tautai, 29, joined from Wakefield in 2015 and was part of the 2016 Grand Final and 2017 World Club Challenge successes over the past 12 months.
Tomkins, 30, returned to Wigan from a spell in rugby union in 2014.
He has played a total of 214 games for the Warriors, and will have an option of an extra season when the deal expires in 2019.
"It is important, not only on the field but off it as well, that we secure the future of our key players and Liam, Joel and Taulima are three of those," Wigan chairman Ian Lenagan said.