An investigation has been launched after Brendan Wall, 44, and 64-year-old Canadian Ivan Chittenden died in Cork on Sunday.
Triathlon Ireland said due to “adverse conditions” its officials told organisers it was not possible to sanction the race.
They stated: “For the Ironman Cork event, in line with normal practice, Triathlon Ireland Technical Officials attended before the start of the race to review 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.”
Phil Harris, a competitor from Co Down, said his thoughts and prayers were with the families of the men.
“The weather conditions changed quite quickly whenever we were getting into the water. It wasn’t so bad once you got through the waves,” he added.
Cork County Council extended sympathies to the families.
“Cork County Council is deeply saddened over the tragic loss of two race participants during the Ironman 70.3 Ireland, Cork 2023 event in Youghal”, it said.
“Our deepest sympathies go out to the families and friends of the athletes at this incredibly difficult time.
“Our thoughts are with those who have been affected and we are currently offering every assistance required to the Ironman Group and all those impacted.
“We wish to express our gratitude to the response agencies involved, including our dedicated fire and emergency personnel, for their unwavering efforts during this difficult time.”
The men had been competing in the half Ironman, a 70.3 mile half triathlon, which had been moved from Saturday to Sunday as a result of Storm Betty.
The event continued with a 90km cycle and a long-distance run.