[3][4] On 6 December 2017, participating in the Brazil Open (long course) in Rio de Janeiro, he broke the South American record in the 1500-metre freestyle with a time of 14:59.01.

On 30 June 2018, participating in the Sette Colli Trophy (long course) in Rome, he broke the South American record in the 800-metre freestyle with a time of 7:50.92.

[12] At the 2019 Pan American Games held in Lima, Peru, Costa won his biggest title, the gold medal in the Men's 1500 metre freestyle, with a time of 15:09.93.

[17] On 19 April 2021, participating in the Brazilian Olympic Selection Trials, he lowered his South American record in the 400m freestyle with a time of 3:45.85.

[18] At the 2020 Summer Olympics in Tokyo, Costa almost broke the South American record in the Men's 400 metre freestyle heats, with a time of 3:45.99.

[22] He did not attend the 2021 FINA World Swimming Championships (25 m), in Abu Dhabi, United Arab Emirates, because he felt some symptoms such as fever and malaise, which made him withdraw from the competition.

[24] It was the first medal by a South American in the men's 400 free from any major international meet since Argentinian Alberto Zorrilla at the 1928 Olympics.

[43] At the 2024 Olympic Games in Paris, Costa reached the final of the 400m freestyle, breaking the Americas record and finishing in 5th place, with a time of 3:42.76, just 0.26 seconds away from obtaining the bronze medal.