Olympic champion Adam Peaty is among the first four swimmers selected by Team GB for the rearranged Tokyo Games.
Peaty, 26, won the 100m breaststroke at Rio Olympics and is joined in the Tokyo team by Duncan Scott, who won two relay silver medals at the 2016 Games.
World medallists James Wilby and Luke Greenbank also have spots at the Tokyo Games - which begin on 23 July.
The four earned places by winning individual medals at the 2019 World Aquatics Championships in Gwangju.
Mark England, Team GB chef de mission for Tokyo 2020, said: "We hope that this confirmation provides clarity and focus for this hugely talented group of swimmers as they continue their preparation for the Olympic Games."