The Netherlands’ Sharon van Rouwendaal made a late move to clinch gold in the women’s 10km marathon swim in the River Seine.
An Olympic champion in 2016, Van Rouwendaal settled for silver at Tokyo in 2021 after missing out on gold by an agonising 0.9 seconds.
The 30-year-old overtook Australia’s Moesha Johnson, who had led for much of the race, in the final lap to snatch victory in two hours three minutes 34.2 seconds.
Johnson finished 5.5 seconds behind to take silver and Ginevra Taddeucci of Italy claimed bronze, while Great Britain’s Leah Crisp finished 20th.
The marathon swimming familiarisation had previously been cancelled after tests showed levels of bacteria in the water had dropped below the required standard.
However, Wednesday’s test went ahead before the 10km race on Thursday.
The water quality of the Seine had been a major talking point before and during Paris 2024, with the men’s triathlon postponed by a day because of the low water quality.
The men’s marathon swim is due to take place on Friday.