Saracens were relegated at the end of the 2019/20 season for salary cap infringements, but secured promotion at the first time of asking last month.
With no relegation this year due to Covid-19, the league has expanded to 13 teams.
Harlequins, who pulled off a thrilling title win last month despite finishing fourth in the table, will open their season away to Newcastle Falcons on Sunday, September 19.
Newcastle could hand debuts to Mike Brown and Nathan Earle, who have made the move from Quins this winter.
London Irish open their season away to Worcester Warriors, before welcoming Sale Sharks to Brentford Community Stadium on Sunday, September 26.
A day earlier, Quins have their first home game, against Worcester Warriors.
Each team will have a bye weekend, when they do not play. Wasps are first, followed by Saracens and Harlequins.
Due to the timing of their bye and two early away games, Saracens have to wait until October 9 to play at the StoneX Stadium, against Newcastle.