The Ironman race in Cork, in which two athletes died, was not sanctioned by Triathlon Ireland.
An investigation is underway after two men died during the swimming event in Youghal on Sunday.
44-year-old Brendan Wall, who was originally from Co. Meath but living in England, and 65-year-old Ivan Chittenden from Toronto in Canada, died in separate incidents while swimming in the sea.
Triathlon Ireland CEO, Darren Coombes, says the sport has had an "impeccable safety record" in its 40 years, and the tragedy has had a "devastating" effect on the triathlon community.
Post mortems were carried out on Monday to determine how each man died.
In a statement released on Monday evening, Triathlon Ireland said. "For the Ironman Cork event, in line with normal practice, Triathlon Ireland Technical Officials attended before the start of the race to review the conditions and carry out a water safety assessment.
"Due to adverse conditions on the day, Triathlon Ireland Technical Officials confirmed to the race organisers that it was not possible to sanction the race.
"As there is an investigation ongoing, at this stage it would not be appropriate for us to make any further comment only to state that Triathlon Ireland will provide any assistance that the authorities require."
Triathlon Ireland is reeling from the news that Ivan Chittenden & Brendan Wall, athletes in the Ironman Cork event in Youghal, tragically died yesterday morning while participating in the race.
Read statement from CEO Darren Coombes
Click the link l https://t.co/glQRIJx5g5 pic.twitter.com/psxgftWV7B
— Triathlon Ireland (@tri_ireland) August 21, 2023