The 32-year-old Fiji international becomes the second recruit for the Canadian club, who have clinched promotion to the Kingstone Press Championship at the first attempt, following the capture of Widnes Vikings centre Tom Armstrong.
Sims has made 85 Betfred Super League appearances since joining the Wolves from North Queensland Cowboys ahead of the 2015 season and played in both the Ladbrokes Challenge Cup final and Betfred Super League Grand Final in 2016.
"I am so honoured to have represented not only this club, but the people of Warrington and hope they know that I put every ounce of energy into this jersey doing the sport I love," Sims said.
CHAMPIONS— League 1 (@League1RL) September 9, 2017
Toronto Wolfpack are promoted to the Championship pic.twitter.com/KgP98Cp4KR
"I wish I could have stayed on longer but it wasn't to be. As my youngest daughter Kaya was born here, I'll always have ties to this great town.
"I'm genuinely really looking forward to this journey with the Toronto Wolfpack but before that I really want to finish off these last two games the right way after a rough season."
Warrington are currently looking for a new coach following the decision, announced at the weekend, to part company with Tony Smith and will have a new-look squad in 2018.
The club have already announced the departure of Kurt Gidley, Brad Dwyer, Andre Savelio, Rhys Evans, Sam Wilde and Peta Hiku.