It’s a triathlon within a triathlon – swim, bike, and run race – and it’s returning to the beaches and waterfront in South Boston this summer.

The 16th annual Columbia Threadneedle Investments Boston Triathlon, set for Sun., Aug. 18, will include Olympic athletes fresh off the Paris Games who will swim at Carson Beach, bike along William Day Boulevard, and run through Moakley Park. 

This year’s event is part of the Supertri League, which has grown to become the world’s premier short-course triathlon organization, and Boston will host the first-ever supertri in the United States.

“Saturday is kids’ day and on Sunday we have Olympic distance and sprint distance races for amateurs,” said Michael O’Neil, president and race director. “This year, we’re adding another ring to the circus and we’re hosting an event called supertri Boston, which is a group out of Europe. They have a global series of five races and the first race will take place at the Boston Triathlon.”

O’Neil, who has a background in the investment field, transitioned to the sports world 17 years ago, but his time in athletics dates back much further. The New Hampshire resident grew up playing sports and was on the ice hockey and soccer teams at Towson University in Maryland. Throughout college, he ran to stay in shape, but it wasn’t until after graduating that the miles built up. 

“After college, I started running more distance, and then I started cycling. And then some of my friends started doing triathlon and so I started racing triathlon myself,” said O’Neil who grew up in Medway. “That’s how I ended up becoming an agent for professionals. It was sort of an accident. I had a friend that made the Olympics, and I helped out with some business stuff and next thing I knew, I was managing a lot of the best professional and Olympic triathletes in the world.”

His work as an agent and the connections he has made with athletes helped him secure supertri at the Boston Triathlon. All that was left to do was speak with officials from the state Department of Conservation and Recreation who run the parks, roadways, and beaches.

“We started to dive into the details, and I think DCR has a lot of pride in the Boston Triathlon because we were organically grown,” said O’Neil. “Just a couple hundred people on a really small footprint 16 years ago.”

The Boston Triathlon group and supertri teams agreed on a three-year partnership, with the first race this summer in Boston. The remaining races will take place in Chicago, London, Toulouse (France’s fourth-largest city), and Neom, a growing urban area in Saudi Arabia.

“The addition of the pro race is strictly a spectator event for our customers,” O’Neil told the Reporter. “It’s going to be really cool to see the absolute best athletes of the sport— the fastest men and women – come and race in Boston.”

Since the Olympics are still months away, O’Neil doesn’t know exactly who will be racing supertri, but the athletes have likely had few opportunities to compete in the United States. 

In addition to these athletes, around 2,500 racers will compete in the Boston Triathlon throughout the weekend.

On Sat., August 17, children under 7 will participate in a 100-yard fun run that will finish at Mother’s Rest near Carson Beach, where O’Neil’s 22-month-old daughter Kirby crawled across the line last year. Named after her Dorchester-born great-grandmother, Kirby will compete again this summer, but this time on foot. Kids older than Kirby can register in one of two Splash and Dash categories.

“There are so many great things tied to the kid’s race,” O’Neil said. “From helping them get the lifesaving skills of learning how to swim, to showing a lot of young kids the positive pathway through sports.” 

O’Neil said he became more aware of the importance of swimming as a life-saving skill after a seven-year-old named Kyzr Willis drowned at Carson Beach in 2016. 

“I grew up fortunate enough to swim. I never had a fear of water, but through my process of trying to make the Boston Triathlon a much more diverse sport, and through the awareness of the tragic accident of Kyzr, I became more focused on it.”

Boston Triathlon took part in initiating Swim Safe Boston, a city program that raises awareness around water and swimming safety by offering free swim lessons, life jackets, and lifeguard information. “The Boston Triathlon, Blue Cross Blue Shield of Massachusetts, and City Hall, were equal funding partners for [Swim Safe Boston] which provided free swim lessons to kids in Boston,” said O’Neil, “mostly in underserved neighborhoods where drowning has become a public health crisis.”

The importance of water safety will be obvious throughout the race weekend. Not only will there be dozens of lifeguards on the shore and in the water but there also will be emergency boats, advanced life support stations, and a full med tent at hand. “We have a real system using chip timing and using bib colors,” said O’Neil. “We will know when every single person entered the water, and every single person exited the water.” These precautions also exist for the adults who compete the following day, when adults can race individually, as relays, or as part of fundraising teams. The various levels of participation make the event much more inclusive, which is important to O’Neil.

“All the work that I did prior to this with the highest-level athletes in the world kind of went out the window. For me, the Boston Triathlon is a way for people to begin their triathlon journey,” he said. 

People typically join a relay team for their first triathlon, so they are not responsible for completing all three events. Those who compete alone, however, are expected to swim, bike, and run. The Triathlon-Sprint is a 750m swim, 17.5K bike, and 5.5K run while the Triathlon-Olympic is a 1.5k swim, 35k bike, and 10k run. 

“The sprint distance is a manageable target. It’s a good first touch point,” explained O’Neil. “Once people do the sprint they want to work up to the Olympic distance. Then a lot of athletes that we start go on to do Iron Mans competition but they always like to come back and race Boston because it was a special first start for them.”

No matter what level of the race an athlete registers for, those who finish will get a memento for their participation at DCR Mother’s Rest Field.  “Our finish line is staged so you get this photo of yourself coming across the finish line.” O’Neil said. In the background, “you see Carson Beach, you see Southie, you see the skyline, it’s pretty incredible.”

Afterward, racers can celebrate on the beach with family and friends and then watch the supertri.

Those interested in registering for the race can do so online, while those interested in watching both the amateur and supertri races can attend in person free of charge. For more information visit Bostontri.com.