Saracens will open the defence of their Aviva Premiership Rugby title at home to Sale Sharks on October 17.
The English league programme is starting later than usual, due to the Rugby World Cup, with the tournament quarter-finals starting on the same day.
As a result, the traditional season opener, the London Double Header, has been moved to November 28, when Saracens will host newly-promoted Worcester Warriors and London Irish take on Wasps at Twickenham.
Harlequins have announced a raft of big signings, including Jamie Roberts, Adam Jones, James Horwill and Tim Visser ahead of their season, open their campaign at home to Wasps, at the Stoop on October 16 — the day before a possible England World Cup quarter-final across the road.
Quins’ director of rugby, Conor O’Shea, said: “We had an incredibly frustrating season last year and we are just focused on getting our best team on the pitch, fit and raring to go.
“We intend to right that wrong next season and get back up the table — and that starts in the first game as we want to win this thing. Anyone who says they don’t want to get off to a fast start would be lying as it takes a huge amount of pressure off you. We’ve just got to be excited by the challenge. Anyone who tries to write us off to win the title this season is foolish.”
In addition to a match at Twickenham, Saracens will make their annual trip to Wembley on April 16, where they will once again face Quins. The champions set an world record attendance for a club rugby match last season when 84,068 watched them beat their London rivals 42-14.
