The local Gerringong Lions junior, who can play up front and in the second-row, had previously agreed to a three-year contract which would have seen him join the Club next season.
Sims, 26, made his first-grade debut for the North Queensland Cowboys during the 2011 campaign and spent four seasons at the Townsville-based club prior to joining the Knights in 2015.
The former Junior Kangaroo has played 98 NRL games in addition to representing both the Fiji Bati and NSW Country Origin team (2012-16) on five occasions each.
“It is welcoming news to have a local junior such as Tariq join the Club earlier than what had originally been expected,” said Director of Rugby League Pathways Ian Millward.
“Tariq is a natural leader having most recently been co-captain of the Newcastle Knights and we know that he will be a good fit for our Club.”
— The Dragons (@NRL_Dragons) June 16, 2016
Sims will join the Dragons later this week.