The Tokyo Olympic Games will start on 23 July, 2021 and will run to 8 August after it was postponed for a year because of the coronavirus pandemic.
The International Olympic Committee’s (IOC) executive board met on Monday to make the decision.
The Olympics will still be called Tokyo 2020 despite taking place in 2021.
The Paralympic Games, originally due to start on 25 August, 2020, will now take place between 24 August and 5 September, 2021.
IOC president Thomas Bach said: “I am confident that, working together with the Tokyo 2020 Organising Committee, the Tokyo Metropolitan Government, the Japanese Government and all our stakeholders, we can master this unprecedented challenge.
“Humankind currently finds itself in a dark tunnel. These Olympic Games Tokyo 2020 can be a light at the end of this tunnel.”
International Paralympic Committee president Andrew Parsons added: “When the Paralympic Games do take place in Tokyo next year, they will be an extra-special display of humanity uniting as one, a global celebration of human resilience and a sensational showcase of sport.
“With the Tokyo 2020 Paralympic Games 512 days away, the priority for all those involved in the Paralympic movement must be to focus on staying safe with their friends and family during this unprecedented and difficult time.”
The decision to postpone both events was taken to protect the health of the athletes and everyone involved, and to support the containment of the Covid-19 virus.
The new dates also took into consideration the rest of the global sports calendar after the men’s football European Championship was postponed to the summer of 2021.
Organiser hope the delay will allow sufficient time to finish the qualification process which will follow the same mitigation measures planned for 2020.
On 24 March, Japan’s Prime Minister Abe Shinzo said the Games would be held in their “complete form” and no later than summer 2021.