2018 At the
African Championships in
Algiers, Algeria, Hafnaoui competed in the 800 meter and 1,500 meter freestyle events, as well as the 4x100 and 4x200 freestyle events. He is only the third swimmer in history to win an Olympic gold medal out of the 8th lane, the slowest qualifying lane. He also placed joint 10th in the
800 meter freestyle, missing qualification for the final. In October, Hafnauoi announced he would be competing at
Etihad Arena in December as part of the
2021 World Short Course Swimming Championships in
Abu Dhabi,
United Arab Emirates. He entered to compete in the 400 metre freestyle and 1500 metre freestyle events. Starting his competition on day one of the championships, 16 December, Hafnaoui swum a 3:40.30 in the prelims heats of the
400 metre freestyle to rank tenth overall. On Day five, Hafnaoui ranked second in the
1500 metre freestyle prelims heats, qualifying for the final with a time of 14:25.77. He won the silver medal in the final of the 1500 metre freestyle on day six in an
African record time of 14:10.94. His time at the 800 metre mark also set a new African record in the 800 metre freestyle at 7:33.69.
2023 On 11 January 2023, Hafnaoui won the gold medal in the 800-metre freestyle at the
TYR Pro Swim Series in
Knoxville, with a time of 7:53.10, which was over three full seconds faster than second-place finisher American
Robert Finke. Two days later, he won the gold medal in the 400-metre freestyle with a time of 3:47.41. On the fourth day, he finished in a personal best time of 15:07.07 in the final of the 1500-metre freestyle, dropping 8.97 seconds from his previous personal best time, to win the silver medal. On 1 March, he lowered his personal best time by 6.83 seconds to a 15:00.24 and won the gold medal in the 1500-metre freestyle at the second stop of the Pro Swim Series, in
Fort Lauderdale, United States. The following day he won the 400-metre freestyle in a time of 3:46.02. On day four of four, he finished in 7:48.50 in the 800-metre freestyle and won the gold medal. At the
2023 World Aquatics Championships held in
Fukuoka, Japan, Hafnaoui won gold in the 800-metre and 1500-metre freestyle events, and silver in the 400-metre freestyle. Hafnaoui will attend
Indiana University in fall 2023 as a member of their men's swimming team. ==2024-2025==