The event was held at
Paris La Défense Arena, which was converted to a swimming pool for the swimming events. Ten heats took place on 30 July 2024, starting at 11:17. Alexy won the eighth heat with the fastest qualifying time of 47.57, while Grousset qualified with the second fastest time of 47.70. Popovici, Németh, Chalmers, Miressi and Pan all qualified. Pan Zhanle qualified with the joint thirteenth fastest qualifying time of 48.40, which
SwimSwam commented "wasn’t a great swim" for him. Between the heats and semifinals of this event, Pan broke the event's Olympic record with his split of the
4 × 100 metre freestyle relay.
South Korean Hwang Sun-woo, who qualified with the sixteenth fastest qualifying time, withdrew from the semifinals in favour of resting for the
4 × 200 metre freestyle relay. This allowed Australian
William Yang to compete in the semifinals instead.
Nepal's
Alexander Shah lowered his country's
national record to 51.91, while Johnathan Silas lowered
Vanuatu's
national record to 59.38, however neither of them were fast enough to qualify. == Semifinals ==