Paris 2024 organisers cancelled training for open-water swimming on Tuesday because of pollution in the River Seine.
It is the fifth time the water quality has forced a swim familiarisation session to be cancelled during these Games, and the men’s race also had to be put back a day.
The latest cancellation comes a day after triathlon’s mixed team relay was held.
All the triathlon swim legs have taken place in the Seine, which is also set to be used for marathon swimming.
Tests showed the levels of the enterococci bacteria in the water had dropped back below the required standard, although E. coli levels were still deemed acceptable.
Another familiarisation session is scheduled for Wednesday, with the women’s 10km race due to take place on Thursday and the men’s race on Friday.