The men's and women's Six Nations will be completed in October after World Rugby approved a new temporary international window.
The remaining rounds of both tournaments will be played on 24 and 31 October.
That will be followed by a rest weekend on 7-8 November before four consecutive rounds of international matches.
In the southern hemisphere, the 2020 Rugby Championship will be played from 7 November to 12 December.
Sanzaar (South Africa, New Zealand, Australia and Argentina Rugby), which organises the competition, has asked New Zealand to host all of the tournament matches.
What's the state of play in the Six Nations?
The tournament was suspended in March because of Covid-19 with four matches in the men's competition to be completed and six in the women's competition.
England are top of the standings in the men's competition with 13 points, ahead of France on points difference. All teams have one left game to play apart from Ireland and Italy, who have two.
Ireland will take on Italy on 24 October, the same day as the Premiership final.
England then plan to play the Barbarians the following day.
The final round of 2020 men's matches will then all take place on 31 October, with Wales hosting Scotland, England playing Italy in Rome and Ireland facing France.
Wales will have to host their home fixtures away from the Principality Stadium after chief executive Martyn Phillips confirmed there will be no more international matches at the ground this year because it is being used as a temporary hospital during the coronavirus pandemic.
This year's autumn Tests are then expected to be replaced by an eight-team tournament in which the Six Nations sides will be joined by Japan and Fiji.
World Rugby chairman Sir Bill Beaumont said in a statement: "The global Covid-19 pandemic has been unprecedented in its impact on society and sport and throughout this process, all parties have sought to deliver the best-possible outcome to support the interests of international and club rugby and the players.
"Agreement and approval of this schedule is exciting for players and fans and an important step in supporting our unions in mitigating financial impact and optimising the sport's return from the pandemic in an equitable way.
"These matches will be greatly anticipated by all, and I would like to thank unions, the international and club competitions and players for their input and the fans for their patience as we have sought to get international rugby back up and running."