The Fastest and Slowest Ironman 70.3 Races of 2025

The 2025 Ironman 70.3 race season is done, and it was another big year with 114 races around the globe including the Ironman 70.3 World Championship in Marbella, Spain. Just over 142,000 athletes raced at least one Ironman 70.3 this year. Of those athletes, just under 135,000 were finishers.

Now that the season is done, I took a look at which events were the fastest and which were the slowest this year. (And if you’re looking for the fastest and slowest full-distance Ironman races in 2025, that’s at this link.)

2025 Ironman 70.3 races at a glance

The total number of races that took place in 2025 was about the same as in 2024. While the calendar remained as busy, there was some turnover in events. We lost nine events from the calendar but gained 10 back from new and returning races. Some of the new races, including Tours Metropole and Rockford, make a showing in some of the fastest or slowest races of the year.

To rank races, I’ve used the average age-group times from each event. Sometimes race courses have to be adjusted on the day. For a fairer comparison, I’ve removed events where course changes – most commonly cancellation of the swim – would have clearly impacted results. A total of 11 events were removed from consideration.

The chart below plots these events by rank and time, from fastest on the left through to the slowest on the right. Races are color-coded based on their location. For clarity, I’ve only labeled the fastest and slowest 10 events of the season.

Europe and North America account for most events, with each hosting roughly a third of all races. The dark blue of European races dominates the top rankings, with South America also making a good showing. North American races fill out the middle ranks more. Asian races appear mostly among the slowest events.

Let’s take a closer look at the fastest and slowest events and how things stack up when we consider individual splits, too.

Fastest 70.3 races of 2025

With a field of competitors who had to qualify, this year’s men’s world championship tops the race ranks. The run is the key differentiator here. Average times from the other races aren’t too different, and we can see that these events were in or near the top five in 2024 as well. Clearly, the 70.3 race roster features a mix of courses that favor fast times.

Slowest 70.3 races of 2025

At the tail end of the ranks we have our first new entry, Rockford in the U.S. The 70.3 in Hawaii also makes an appearance for the U.S. Asia completes the list of slowest five with Kenting, Subic Bay, and Goa in India. Goa maintains its place as the slowest 70.3 event.

Fastest and slowest 70.3 swim times of 2025

There’s a limited relationship between races ranking for swim speed and overall speed, as the swim obviously takes up the shortest portion of a course. The fastest swims are recorded by a mix of events found mostly in the front and middle of the overall race rankings. The slowest swims tend to be among the slowest races, with a handful in the middle.

Most of our fastest swim splits came from the U.S. What they all share in common is a downriver swim aided by a current, leading to blistering speeds compared to your typical 70.3 event.

There’s a mixed group of Asian and North American races making up the slowest five Ironman 70.3 swims of 2025. That includes one new entry, Ironman 70.3 Boise, with a reservoir swim that proved to be among the slowest.

Fastest swim times

Slowest swim times

Fastest and slowest 70.3 bike times of 2025

The bike is the longest element of an Ironman 70.3 and has a strong relationship with the overall ranking of an event. The majority of our fastest races rank in the top 20 for average bike splits. The relationship is weaker for slower races, but generally, slower races still have the slower bikes.

Europe tops the ranks for bike splits, including a new entry for Tours Metropole – Loire Valley. A number of these events had already made an appearance at the top of the overall ranks.

Our slowest bike split comes from the women’s world championship in Marbella. Bear in mind this is the only event whose average splits reflect women’s times alone. Most other events in the bottom five are regulars at the tail end of the ranks. Nice comes second from last, likely reflecting its extended climb and descent.

Fastest bike times

Slowest bike times

Fastest and slowest 70.3 run times of 2025

There is a strong relationship between ranking of run splits and overall splits. Particularly for the slowest races, the run is clearly their most defining factor. The relationship is weaker for the fastest races.

Both the men’s and women’s world championships appear in the top five fastest run splits. This is in stark contrast to the women’s race, which had the slowest average bike split of the season. Outside of these selective races, there are two European events, Kraichgau and Vichy, and Buenos Aires in South America.

Asia hosts most of the slowest run courses. Heat and humidity is typically one of the major challenges when racing these events. Rockford appears again with the second slowest average run of 2025. It was a hot day for the inaugural race, and it shows in its run time.

Fastest run times

Slowest run times

There are a lot of options for those who race Ironman 70.3. These averages and relative rankings of races can help you find the events most likely to give you a fast time – or a challenging course.