OWS Fatalities Research

While there is no single official public database that tracks every death specifically during the swim leg of IRONMAN and IRONMAN 70.3 events worldwide, I've compiled data from media reports, race statements, academic studies, and community-maintained lists.  I suspect that death counts are higher than what has been published for several reasons: 

1. Any participants in distress who are either extricated from the water or are already on-land are transported off-site, so if they pass away, it will not have been during the event itself, and media would not have published the information due to HIPAA

2. IRONMAN does not always publish statements post-fatality

   
   

Summary of available info online

• Roughly 45–60 deaths occurred during the swim portion of IRONMAN-branded events worldwide from 2016–2025

• About 70–90% of all triathlon fatalities occur during the swim leg. (Source: Harris KM, Henry JT, Rohman E, Haas TS, Maron BJ. Sudden Death During the Triathlon. JAMA. 2010;303(13):1255–1257. doi:10.1001/jama.2010.368)

• Possibly: deaths initially labeled “drowning” are later believed to involve a primary cardiac event occurring in the water that resulted in the participant not being rescued in a timely manner (Source: https://www.researchgate.net/publication/320207422_Sudden_Death_During_Triathlons_The_Heart_of_the_Swim)

  
  

Demographics/Volumetrics 

A major medical review of USA Triathlon-sanctioned events found:

• 135 deaths/cardiac arrests from 2006–2016

• 90 occurred during the swim (~67%)

• Victims were overwhelmingly:

  • Male (85%)

  • Middle-aged or older

  • Average age ~47 years

A more recent case series focused specifically on IRONMAN 70.3 races (2017–2022) found:

• 16 deaths total

• 87.5% during the swim

• 68.8% male

• Average age 48

• Leading causes:

  • heart attack

  • drowning

Estimated swim-leg deaths at IRONMAN events (2016–2025)

The table below combines published studies, media reports, and known fatality lists. Because reporting is inconsistent, I'm assuming these are minimum confirmed counts, not exact totals.

Year	Estimated Swim Deaths at IRONMAN / 70.3 Events	Notable Events
2016	~3–5	Several 70.3 incidents in US/EU
2017	~4–6	Augusta 70.3, regional races
2018	~4–5	Barcelona, Taiwan, others
2019	~7–9	Wisconsin 70.3, South Africa 70.3
2020	0–2	COVID-related cancellations reduced races
2021	~4–6	Return of global racing
2022	~5–7	Multiple North American races
2023	~6–8	Ireland/Cork double fatality, Memphis 70.3
2024	~4–6	Swansea 70.3 and others
2025	~5–7	Multiple swim emergencies reported
Total	~45–60

These estimates align with broader triathlon fatality trend analyses showing that IRONMAN races account for roughly 40% of triathlon deaths globally in recent years. (Source: https://www.thetemponews.com/p/analysis-safe-triathlons)

Demographic breakdown of swim-leg fatalities

Across the available studies and event reports:

Demographic	Typical Pattern
Sex	~70–85% male
Average age	Late 40s to early 50s
Age range	Most commonly 40–65
Experience level	Often experienced amateurs, not beginners
Cause of death	Drowning secondary to cardiac event is common
Race type	More common in long-course and 70.3 events
Geography	North America has the highest absolute count

(Source: https://www.researchgate.net/publication/384519491_Ironman_Triathlon-Related_Fatalities_From_2017-2022_A_Case_Series_792)

Commonly reported contributing factors

Researchers and race physicians repeatedly cite:

• Delayed rescue visibility in open water

• Sudden cardiac arrhythmia

• Underlying coronary disease

• Panic/anxiety in open water

• Cold water shock

• Sudden immersion pulmonary edema (IPO/SIPE)

• Crowded swim starts

(Source: https://en.thairath.co.th/sport/others/2928399)

Notable documented swim-leg fatalities (recent decade)

A few publicly reported cases include:

Event	Year	Athlete Age	Reported Cause
Ironman 70.3 Wisconsin	2019	61	Drowning
Ironman 70.3 Wisconsin	2019	38	Drowning
Ironman 70.3 South Africa	2019	48	Drowning
Ironman Cork (Ireland)	2023	40s–60s	Swim distress
Ironman Memphis 70.3	2023	not public	Cardiac arrest/swim
Ironman 70.3 Swansea	2024	61	Swim distress
Ironman Texas	2026	38	Drowning

(Source: https://en.wikipedia.org/wiki/List_of_multisport_and_triathlon_fatalities)

How can we do better?

These fatalities are frequently traced to systemic issues that we need to address as a community. While heart attack and drowning are the leading reported causes, researchers suggest that primary cardiac events occurring in the water often result in drowning due to delayed rescue.

The scientific consensus identifies several preventable contributing factors, including:

• Delayed rescue visibility in open water (no tow float swim buoys currently allowed)

• Crowded swim starts

• Cold water shock and sudden immersion pulmonary edema (IPO/SIPE)

  
  

On top of all that, the operational response to emergencies is gravely insufficient. Case history, including the drowning of my colleague Dan Winkler at Ironman Galveston, TX in 2022, demonstrates that race officials are often unaware an athlete is missing, or can’t extricate the participant from the water in time to provide resuscitation efforts.  Events have historically continued even after a participant's death, with organizers simply rerouting competitors instead of stopping the race to make sure the remaining athletes are safe.

The Portland Bridge Swim requires (and even provides) each swimmer to wear a standard tow buoy so our safety team is able to locate and identify swimmers quickly. In a moving river with high turbidity, it's imperative a swimmer stay at the surface to be extricated quickly in the event of an emergency. Even with small-scale group starts of 20-25 people, we've never seen an issue with participants getting tangled in the tow float straps or prevent the swimmers from making forward progress.

My goal in publishing this post is to make other race directors and swimmers realize that tow floats are an essential piece of safety equipment, and to encourage other event organizers to try using them for their upcoming events. I'd love to learn more about the experience from events switching from not using tow floats to mandating or allowing them.

If you have questions about how the Portland Bridge Swim uses tow floats as part of our safety plan, or would like to review how to improve safety with your event, feel free to contact me: hello@swimwildwaters.com.