The swimming competitions at the 2020 Summer Olympics in Tokyo were due to take place from 25 July to 6 August 2020 at the Olympic Aquatics Centre. Due to the COVID-19 pandemic, the games were postponed to 2021. However, their official name remained 2020 Summer Olympics with swimming events set for 24 July–1 August 2021 and marathon swimming set for 4–5 August 2021.
The men's 50 metre freestyle event at the 2020 Summer Olympics was held from 30 July to 1 August 2021 at the Olympic Aquatics Centre. It will be the event's tenth appearance, first held in 1904 and then at every edition since 1988. The event is nicknamed the "splash and dash" event.
The men's 200 metre freestyle event at the 2020 Summer Olympics was held from 25 to 27 July 2021 at the Tokyo Aquatics Centre. There were 39 competitors from 30 nations, with the ultimate numbers determined through the ongoing selection process, including universality places.
The men's 400 metre freestyle event at the 2020 Summer Olympics was held in 2021 at the Tokyo Aquatics Centre. It was the event's twenty-seventh consecutive appearance, having been held at every edition since 1904.
The women's 50 metre freestyle event at the 2020 Summer Olympics was held from 30 July to 1 August 2021 at the Olympic Aquatics Centre. It was the event's ninth consecutive appearance, having been held at every edition since 1988.
The women's 100 metre freestyle event at the 2020 Summer Olympics was held from 28 to 30 July 2021 at the Tokyo Aquatics Centre. It was the event's twenty-fifth consecutive appearance, having been held at every edition since 1912.
The men's 100 metre backstroke event at the 2020 Summer Olympics was held from 25 to 27 July 2021 at the Tokyo Aquatics Centre. It was the event's twenty-sixth appearance, having been held at every edition since 1904 except 1964. Moreover, these Games marked the first time when the men's sprint backstroke event was held in Tokyo, as the event was not included in the swimming program in 1964.
The men's 200 metre backstroke event at the 2020 Summer Olympics was held from 28 to 30 July 2021 at the Tokyo Aquatics Centre. There will be approximately 30 competitors from approximately 20 nations, with the ultimate numbers determined through the ongoing selection process, including universality places.
The women's 100 metre backstroke event at the 2020 Summer Olympics was held from 25 to 27 July 2021 at the Tokyo Aquatics Centre. It was the event's twenty-third consecutive appearance, having been held at every edition since 1924. An unusual occurrence happened where the Olympic record for this event was broken three times in a single day and five times through the course of the entire competition.
The women's 100 metre breaststroke event at the 2020 Summer Olympics was held from 25 July to 27 July 2021 at the Tokyo Aquatics Centre. It was the event's fourteenth consecutive appearance, having been held at every edition since 1968.
The women's 200 metre breaststroke event at the 2020 Summer Olympics was held from 28 to 30 July 2021 at the Tokyo Aquatics Centre. It was the event's twenty-third consecutive appearance, having been held at every edition since 1924.
The men's 200 metre individual medley event at the 2020 Summer Olympics was held from 28 to 30 July 2021 at the Tokyo Aquatics Centre. It was the event's twelfth appearance, having been first held in 1968 and 1972 and then at every edition since 1984.
The men's 400 metre individual medley event at the 2020 Summer Olympics was held on 24 and 25 July 2021 at the Tokyo Aquatics Centre. It will be the event's fifteenth consecutive appearance, having been held at every edition since 1964.
The women's 400 metre individual medley event at the 2020 Summer Olympics was held on 24 and 25 July 2021 at the Tokyo Aquatics Centre. It will be the event's fifteenth consecutive appearance, having been held at every edition since 1964.
The women's 4 × 100 metre freestyle relay event at the 2020 Summer Olympics will be held in 2021 at the Tokyo Aquatics Centre. It will be the event's twenty-fifth appearance at the Olympics, having been held at every edition since 1912.
The men's 4 × 200 metre freestyle relay event at the 2020 Summer Olympics was held on 27 and 28 July 2021 at the Tokyo Aquatics Centre. It will be the event's twenty-sixth consecutive appearance, having been held at every edition since 1908.
The women's 4 × 200 metre freestyle relay event at the 2020 Summer Olympics was held in 2021 at the Tokyo Aquatics Centre. It was the event's seventh consecutive appearance, having been held at every edition since 1996.
The men's 4 × 100 metre medley relay event at the 2020 Summer Olympics was held on 30 July and 1 August 2021 at the Tokyo Aquatics Centre. It was the event's sixteenth consecutive appearance, having been held at every edition since 1960.
The mixed 4 × 100 metre medley relay event at the 2020 Summer Olympics was held in 2021 at the Tokyo Aquatics Centre. These Games marked the first time to feature a mixed-gender swimming event in the program. Each 4-person team features two male and two female swimmers.
The women's 4 × 100 metre medley relay event at the 2020 Summer Olympics was held on 30 July and 1 August 2021 at the Tokyo Aquatics Centre. It was the event's sixteenth consecutive appearance, having been held at every edition since 1960.
