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How Long is Ironman? A Look at How the Ironman Distance Came to Be

An Ironman distance triathlon—sometimes called the iron-distance—is 140.6 miles. But why?

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We’ve all been there: You tell a non-triathlete friend or family member that youre training for a triathlon, and you get the following questions: “Youre doing an Ironman? That one in Hawaii? It’s how many miles?!”

Of course, not all triathlons are Ironman races and you can be a triathlete without ever doing an Ironman brand or iron-distance race. Any multisport event consisting of swimming, biking, and running is a triathlon. Basically, an Ironman is a triathlon, but a triathlon doesn’t have to be an Ironman. Still, there’s something that draws people to the epic nature of the Ironman distance and can make it synonymous with the sport in popular culture. 

How was the Ironman distance established? It all started back in Honolulu in 1978 with the inaugural “Hawaiian Iron Man Triathlon.” Then, in 1980, ABCs Wide World of Sports” brought coverage of the race into living rooms around the world. Since then, Ironman triathlon has conjured up images of swimming 2.4 miles in the aquamarine waters off Dig-Me Beach, biking 112 miles through the black lava fields down Queen K Highway, and running 26.2 miles in the brutal heat of the Energy Lab in Kona, Hawaii.

How did that Ironman race come to be?

The history behind the Ironman distance

Many different stories have circulated over the past 44 years about the origin of the Ironman distance. Some say it was a drunken bet or a masculine test of will. But the only way to separate fact from fiction, especially when it comes to the details of the original course, is to go straight to the source: John and Judy Collins. 

In 1974, the Collins family participated in the Mission Bay Triathlon in San Diego, one of the first early triathlon events in the world. They enjoyed it so much they proposed an idea to their local swim club coach and, in 1975, the first Coronado Optimist Club Triathlon was held. Its now known as the longest continuously running triathlon in the world. 

After the Navy sent the Collins family to Hawaii, they joined the Waikiki Swim Club and participated in the Waikiki Rough Water Swim—which is actually 2.385 miles. They also joined the Mid-Pacific Road Runners Club and ran the Honolulu Marathon. Enjoying these events, they wanted to create a long distance triathlon on the island, but they were missing one thing: the bike leg. An avid cyclist, John suggested a third annual event, the Around Oahu Bike Ride (originally 115 miles and held over two days). So, how did the Ironman bike distance get shortened to 112 miles? 

We were thinking you could compete around the entire island by starting the swim at Kapiolani Park and then bicycling counter-clockwise to the start of the Honolulu Marathon by cutting three miles off the estimated bike route distance,” Judy Collins said. It was a perfect fit and a wonderful moment to figure that out.”

Thus, the distances for the first Hawaiian Iron Man Triathlon were set. 

Judy and John included a handwritten note on that first course description that read: “Swim 2.4 miles! Run 26.2 miles! Bike 112 miles! Brag the rest of your life!” The event would be the first triathlon in Hawaii and the first long distance Ironman triathlon in the world. 

While many are familiar with these distances today, theres one important detail not many people know. The best part of it, for me, was that when we added up the three distances, we realized it would equal 140 miles, which is the run perimeter of Oahu,” Judy said. That always made it special that the mileage was equal to circumnavigating the whole island. It turns out that not many people knew that once the race moved to The Big Island.”

RELATED: The Origins of Ironman: How Kona Became Kona

The original flyer for the Hawaiian Iron Man Triathlon. (Photo: Courtesy of John & Judy Collins)

How far is an Ironman?

These days, you can find Ironman and iron-distance races around the globe, from France and Queensland to Alaska and New York. Some have ocean swims, while others take place in a river or lake. There might be a hilly bike course combined with a flat run course, or vice versa. But while the incredible destinations may vary, the distances remain the same. 

For a full Ironman or iron-distance triathlon, athletes begin with a 2.4-mile swim, continue to a 112-mile bike ride, and finish with a 26.2-mile run. 

However, it’s important to remember that while the term “Ironman” is commonly used to refer to a specific distance triathlon, it is also the name of a branded race company. The Ironman brand also puts on shorter Ironman 70.3 races (also known as a half-Ironman). These races cover half the distance of a full Ironman with a 1.2-mile swim, 56-mile bike, and 13.1-mile run.

Also, there are iron-distance events that cover the same mileage, but don’t fall under the Ironman brand of races. Examples include popular events like Challenge Roth and the extreme Norseman Tri, where athletes cover the same epic distances but without the Ironman moniker.

Ironman Distances
Swim Bike Run
2.4 miles 112 miles 26.2 miles

How long does it take to do an Ironman?

Most Ironman races have a 17-hour cut-off in order for an athlete to be considered an official finisher. (Fun fact: in the first Ironman in 1978, John Collins finished in ninth place with a time of 17 hours and 3 seconds.) Historically, with a 7 a.m. start, that used to mean a midnight finish line. However, since the incorporation of wave starts and rolling starts to eliminate crowding, cut-off times can vary by individual with differing checkpoints throughout the course.

The fastest Ironman times in the world are 7:21 for men and 8:18 for women, but what about a regular age-grouper? Finding a true average Ironman time can be tricky, because while the swim-bike-run distances are the same, courses differ in weather conditions and elevation. Average times also vary based on age group and gender. But, according to calculations of hundreds of results, the average male Ironman finish time is 12:27 and the average female Ironman finish time is 13:16.

RELATED: What is a ‘Good’ Triathlon Time?

Why is it called an Ironman?

On Feb. 18, 1978, 15 athletes participated in the first Hawaiian Iron Man Triathlon. The Collins family decided to name the race after one of Johns shipyard co-workers who received the nickname Iron Man,” because he could keep running forever without slowing down.

A lot has changed since that first year, when the cost of entry was $5 and the award was a copper pipe, stick figure trophy welded by John. We thought it would be really good to have an award for every finisher that was identical—just to emphasize this wasnt a race. It was a finishers event, where the whole goal was to finish,” Judy said.

That initial spirit lives on today with each athlete who finishes getting a finishers medal and t-shirt.

Its still amazing to Judy how those first races planted a seed that would grow into a global phenomenon bringing the love of triathlon to people around the world. When we started the race, we intended to retire on the island and to be in the race every year,” she said. We pictured a local event, not very big. The swim, bike, and run legs would connect the courses of those three annual events in Honolulu. I think how lucky it was for the future of endurance triathlon that 1981 race director Valerie Silk moved Ironman to a place where it could grow.”

In the new home, Kona, Hawaii, the same Oahu distances were in a new geographic place. It was an easier swim than Waikiki with a much harder bike course and a hotter marathon with not much shade.”

RELATED: Triathlete’s Complete Guide on How to Train for an Ironman

You Are An IRONMAN!”

Completing a 2.4-mile swim, 112-mile bike, or 26.2-mile run is a feat in its own right. For even the most experienced athletes, combining all three into one day can seem insurmountable.

Anything is possible,” said Mike Reilly, who has called thousands of finishers across the line as the “Voice of Ironman.” Reilly’s famous catchphrase—“You are an Ironman!”—is something you’ll only hear at the finish line of Ironman brand races and something athletes look forward to at the end of their journey.“Hundreds of thousands of people do it every year. When people tell me, I dont believe I can do it,’ I tell them that when they start believing that they can, they will.”

“The number one lesson in Ironman is finishing what you start. Whether its a pro or the final age-grouper I bring in toward that midnight hour, they believed they could get to the start line, and the finish line. They did the work and put in the time.”

No matter how long it takes, completing the Ironman distance is an incredible accomplishment. As that original flyer said, you can now “Brag the rest of your life!”

Theres something I want you to remember—something I want everyone to remember wherever they do an Ironman,” Judy said. Those distances that youre completing connect you to their history and location in Hawaii. They have special meaning. To me, thats why those distances are magical.”