Sharon van Rouwendaal of the Netherlands made a late surge to win gold in the women's 10k marathon swimming at the Paris Olympics on Thursday.

Van Rouwendaal won with a time of 2hr 03min 34.2sec, with Australian Moesha Johnson taking silver 5.5 seconds behind and Italy's Ginevra Taddeucci claiming bronze.

The race took place on the River Seine with the Eiffel Tower in the background after water pollution levels were deemed sufficiently safe for competition.

It was the third straight Olympic medal in the event for Van Rouwendaal, the gold medallist in Rio in 2016 and silver medallist in Tokyo, who made her move past Johnson around a pilon coming under the Pont des Invalides bridge.

The 30-year-old Dutchwoman, who was also world champion in Budapest in 2022, never looked back as she powered her way to the finish.

Van Rouwendaal said her victory was dedicated to the memory of her pet dog Rio, who died in May.

"Swimming is my everything, but so was he. When there were complications in May, he died shortly afterwards. Then my world stood still and I wanted to swim for him one more time," she said.

"My father said: swim one more time and do it for him. And that's what I did," she added.

It was a crushing blow for Johnson who had led from the half-way mark onwards and was out front with the top three having broken well clear of the field going into the final lap.

But the Australian said she had no regrets about her approach to the final stages when victory slipped from her grasp.

"Under that bridge, there are these pillars and the current's really strong coming through it and there was two options and I knew whatever option I took, Sharon behind me would have taken the other one and we just had to fight it out and see which route was quicker or who was stronger and obviously that's kind of where she passed me into the gold medal position," she said.

"But I'm happy with my choice, I've committed to it and it's just such a tactical race and there were so many ifs, buts and maybes that could have happened in that race and to come out with a medal is just, it's unbelievable," she said.

The decision to hold the race on the river produced a glorious spectacle but had caused headaches for organisers.

The triathlon was badly disrupted by poor bacterial readings last week, with all swim training sessions cancelled and the men's individual race postponed by 24 hours until Wednesday.

Training for the 10k race had been cancelled due to the water pollution levels.

But Johnson said the water quality had not been bad.

"I'll go home and have some antibiotics, that was part of my plan, but I've tasted worse," she said.