Ledecky wrote back, and the pair have not stopped communicating. As Ledecky learned more about Olmstead’s swimming career, she gained a deeper appreciation for her own career trajectory. That Olmstead did not have an opportunity to compete in college reminded Ledecky how fortunate she was to have had the chance to compete in multiple Olympics and the choice to swim in college or turn professional.

“I think a lot of people take for granted how lucky we are now to have college sports for women and to have the opportunities that we do,” she said.

Their friendship also helped ease Ledecky’s transition during her first year away from home, as she settled into life on the opposite coast from where she was born and raised. Olmstead and her husband, Bob, made the two-and-a-half-hour drive from their home in Sacramento to attend two of the Stanford women’s home meets during Ledecky’s freshman season, standing in for her parents when they could not be there to cheer for her.

The Pro Swim Series meet here was the first time Olmstead had seen Ledecky compete in an Olympic 50-meter course. They arrived at the same time at the center that Olmstead helped build — she was one of Haines’s first star athletes at the Santa Clara Swim Club — and greeted each other warmly in the foyer. A few black-and-white portraits are on prominent display there, including one from the 1960s of Olmstead posed sitting on a starting block in street clothes, gazing over her right shoulder.

“Wow,” Ledecky said. “Look at the hair flip.”

Ledecky mentioned that she had watched a YouTube clip of Olmstead racing in the 250-yard freestyle at the nationals in 1960 without, as was custom then, the aid of a cap, goggles or flip turns. Olmstead asked what she thought of her stroke. “It was really good,” Ledecky said. “I was impressed.”