Ironman 70.3: A Course Comparison

Tanner Sax
5 min readFeb 8, 2019

When I set the goal of participating in my first Ironman triathlon event, I had no idea, four months later, the rush that I would feel as I crossed the finish line.

After graduating from college in May 2018, I received a Specialized Roubaix road bike as a graduation present. Receiving this bike was my initial motivation to give the sport of triathlon a try. I was already acclimated to running through various sports and individual exercise and biking as a means of transportation during the summers. I had never swum competitively.

But if there’s one thing I’ve learned from my experience, it’s that consistency and intention can take you anywhere.

After four months of waking up for numerous 6 a.m. lake swims, 40-mile bike rides through the Adirondacks that took me pedaling into the night and runs that made me feel like my legs would give out, I finally competed in the Atlantic City Ironman 70.3 in September 2018.

The two main Ironman sanctioned races are Ironman 140.6 and Ironman 70.3, with the numbers in their titles representing the total distances. The goal of this analysis is to give athletes a better indication of which Ironman 70.3 course is best suited for their next race, and how to evaluate their performance on that course.

The Ironman 70.3 consists of a 1.2-mile swim, 56-mile bike, and a 13.1-mile run. In this analysis, the race results for Ironman 70.3 events around the world are collected through a web scrape. In total, there are 117 different courses analyzed with a total of 145,457 individual participant times. The results collected reflect the most recent year that the race was run on each course. There were five courses that had to be eliminated from the analysis due to cancelled and shortened swims — Pula, New Orleans, Busselton, Weymouth and Marbella. Then, six courses that were part of a championship race were dropped. This is because the intention of this analysis is to create a comparison of the average Ironman participant. Including the race times from championship level competitors would decrease the analysis’ accuracy.

The following graphs shows the courses listed by average overall race times. The first column contains the average overall time for each course. The fastest courses appear at the top and continue to get slower towards the bottom. The next columns contain the average swim, bike, then run times. The bars are colored according to average times, with the fastest times green and slowest red. It is important to note that the transition times are not included.

Graph 1 contains only U.S. courses, Graph 2 contains only foreign courses, and Graph 3 contains both U.S. and foreign courses combined.

Graph 1

Graph 2

Graph 3

Ironman 70.3 Turkey produced the fastest times in the world, with Sunshine Coast following. The amount of red that shows in the swim column for the fastest courses is an indicator that the bike and run legs of the race contribute more to the overall time. This is because both events take more time on average and have greater variances.

This chart can be used to decide which course is best suited for different types of athletes, based on which leg of the race the athlete excels in the most.

For example, if the athlete is a great runner but not as comfortable in the swimming and biking legs, then Panama could be a good choice for that competitor. This is because the average run times on that course tend to be longer, so athletes can improve their overall time relative to others by running a strong half marathon.

Since the races take place in different locations, the courses can have drastic differences in elevation change, climate, swim conditions and number of participants. This can have a large effect on the average overall time of participants across different courses, as the chart shows.

A common problem for many triathletes is that they don’t know how their race time transfers to another course. This makes it difficult to know if the time on one course is better or worse than another.

A method of discovering this information is through statistical analysis that involves computing the Z Score to standardize the courses. The Z score is the amount of standard deviations that a value is above or below the mean.

By computing the Z score of my race times for the Ironman 70.3 Atlantic City, I can view my expected times on other courses based on the mean and standard deviation of those courses.

The following table shows my Atlantic City Ironman 70.3 times and my relative course times in each of the different courses analyzed, listed in alphabetical order.

This analysis will give me a better understanding of how to interpret my results in my second Ironman 70.3 event. Atlantic City appears to have relatively longer swim times, a fast bike course, and an average-to-fast run course. If I were to compete in the Lake Placid event next, I won’t be so surprised if my times are significantly longer because of the mountainous nature of the course. It has a very slow bike course, which is the main contributor to the overall race time. Either way, I would still probably be determined that I could have done better, but I guess that’s what keeps it interesting, right?

A further analysis could compare the race times year over year, since this analysis only takes into account the most recent year that the race was conducted. This would give an indication if factors such as weather differences or changes to the course have a significant effect on times.

(If you are interested in finding your own relative Ironman 70.3 course times based on a previous race*, you can input your race times on my site at and I will be happy to run the analysis for you.)

*Using times from an event on the date listed ensures accuracy

** The 10/13/2018 North Carolina event was cancelled, the correct date is 10/21/17