After failing a drug test, Yefimova was disqualified from competition for 16 months, from October 2013 to February 2015, was stripped of her results and medals at the 2013 European Short Course Championships, and four of her world short-course records were invalidated.

The following year, at the 2011 World Aquatics Championships, she won the silver medal in the 200 metre breaststroke with a Russian record time of 2:22.22, finishing less than one second behind the gold medalist in the event Rebecca Soni of the United States.

[16][19][20][21] In August 2015, after 16 months of disqualification due to the positive drug test, Yefimova competed at the World Aquatics Championships in Kazan.

She won a gold medal in the 100 metre breaststroke with a time of 1:05.66 that was seven tenths of a second faster than the next fastest swimmer, Rūta Meilutytė of Lithuania.

[38] Yefimova was also criticized for taking performance-enhancing drugs by other swimmers, including Lilly King, who won the gold medal in the 100 metre breaststroke.

"[39][40] After Yefimova won silver in the 100 metre breaststroke, ESPN pushed back directly against her presence at the 2016 Olympic Games, stating "Yulia Efimova shouldn't have been in Rio at all".

[42] At the 2017 New South Wales State Open Championships in March in Sydney, Australia, Yefimova won the 200 metre breaststroke event with a time of 2:28.80.

[47][48][49][50] Three days later, she won the 200 metre breaststroke in 2:19.64, which was over two seconds faster than the next fastest swimmer and silver medalist in the event, Bethany Galat, and gave her the fifth World Championships title of her career.

[57] For the breaststroke leg of the 4 × 100 metre medley relay, Yefimova split a 1:03.95, helping win the gold medal and set a new championships record at 3:54.22.

[61] Yefimova was one of three swimmers to win four gold medals at the 2018 European Aquatics Championships along with Adam Peaty of Great Britain and Sarah Sjöström of Sweden.

[62] At the 2019 World Aquatics Championships in Gwangju, South Korea in July, Yefimova won the silver medal in the 100 metre breaststroke, finishing less than six-tenths of a second behind Lilly King of the United States with a time of 1:05.49.

[67][68] On 19 May 2021, Yefimova placed fourth in the 100 metre breaststroke at the 2020 European Aquatics Championships held at Danube Arena in Budapest, Hungary.

[84] On the first day of competition, Yefomiva won the gold medal in the final of the 200 metre breaststroke, finishing over one second ahead of the next fastest swimmer with her time of 2:22.19.

[91] In the morning of day one of competition, Yefimova ranked third across all prelims heats in the 200 metre breaststroke with her time of 2:25.54 and qualified for the final in the evening.

[93][94] The following morning, on 29 October, Yefimova advanced to the final ranked second for the 100 metre breaststroke from the prelims heats where she swam a 1:06.24.

[96][97] On the last day of World Cup competition, Yefimova ranked first in the prelims heats of the 50 metre breaststroke with a time of 30.21, two-hundredths of a second ahead of the next-fastest competitor.

[103] The second ban for her nationality came from FINA, which barred all Russians and Belarusians from their competitions effective 21 April 2022 and lasting at least through 31 December 2022.

[105] In April 2023, World Aquatics (formerly FINA) provided clarity that it had extended its 2022 ban in a back-acting manner, and the sanctions were indefinitely still in effect.

[106] Legend: NR — Russian record The following medals Yefimova has won at Swimming World Cup circuits.