Brazil competed at the 2013 World Aquatics Championships in Barcelona, Spain between July 20 and August 4, 2013.

César Castro is the only athlete to compete.

[1] Brazil qualified six athletes (4 men and 2 women) to compete.

[2] Brazilian swimmers earned qualifying standards in the following events (up to a maximum of 2 swimmers in each event at the A-standard entry time, and 1 at the B-standard):[3] A total of 23 swimmers (13 men and 10 women) are selected to compete at the World Championships, including world record holder and undisputed superstar César Cielo and Olympic silver medalist Thiago Pereira.

[5] * Reserves Brazil qualified a women's team.