For Nancy Smith, swimming is in her blood, and she does not plan to give it up any time soon.

The 78-year-old was one of 315 athletes to compete in the Buzzards Bay Swim on June 30. She hasn’t missed the annual Buzzards Bay Coalition fundraiser since 2000 -- although due to the event’s cancellation last year she was not able to swim, but did fundraise.

Despite facing a navigation issue, this year’s event featured magnificent waters and a big crowd. She finished with an overall time of 55:18. It was within her goal of completing the 1.2-mile course in outer New Bedford Harbor from the South End of New Bedford to Fort Phoenix Beach in Fairhaven in under an hour.

A chance encounter with an old friend at the YMCA in 1999 led her to compete in her first Buzzards Bay Swim a year later in 2000 at the age of 60. She elected to have an escort with her on a boat, but the very next year she decided to continue, this time by herself.

She’s been at it ever since. She begins her training as soon as possible, usually in the spring, and even after the event, she was back out at Round Hill Beach on July 1 for a swim.

In addition to the swimming aspect, Smith sees firsthand the effect the work of the coalition has on improving water quality in the region. With five grandchildren, she hopes to help leave the world a better place for them. She was one of the event’s top individual fundraisers, bringing in $2,870 to benefit the coalition.

“When you’re getting to be as old as I am, you start to want to leave something behind,” Smith said. “I just think we ought to be good stewards for the environment.”

Just under 20 Dartmouth residents participated in the swim in total this year. Mitchell Alves, 31, achieved the fastest swimmer in his age group of 30-34-year-olds.

Before the event, swimmers raised $146,500 to support the coalition’s work in protecting clean water, conserving land, and educating people across the Buzzards Bay region.

Donations are still being accepted until July 31, as the organization’s goal is to raise $157,000 to trigger an additional $50,000 donation from Larry Fish’s Fish Family Foundation. Visit savebuzzardsbay.org/swim to donate.