Unless you know who Shannon McCrillis is, seeing her on a paddleboard miles from shore during winter might be cause for alarm.

A Wareham resident and experienced paddleboarder, McCrillis has taken trips that range from 12 to 20 miles long. She doesn’t let cold weather keep her off the water; she paddles year round when the sea is calm.

At first, McCrillis' long trips were such an alarming sight for people that they made calls to the police, concerned that she may be in distress.

“Everyone from Swifts Beach was keeping an eye on me,” she said. “I had neighbors calling to make sure that I was OK.”

While paddleboarding is becoming increasingly popular across the South Coast, McCrillis said there aren’t many who travel the distances she does, and she understands the initial concern. When people see someone who is that far out with nothing but a board and paddle, she said, it’s better to make sure they are in control.

The sport is similar to surfing, but paddleboarders don’t wait for waves. Instead, they stand up and propel themselves through the water with a paddle.

Next month, McCrillis will participate in her longest paddleboarding trip to date – a 34-mile journey from Plymouth to Wellfleet known as the Cape Cod Bay Challenge. Participants launch from Plymouth at 7 a.m. on Aug. 27. The journey takes between 10 and 12 hours to finish.

Now in its ninth year, the event is the longest stand-up paddleboarding event on the East Coast. It serves as a fundraiser for Christopher’s Haven, a Boston-based nonprofit that helps families with children battling cancer.

McCrillis credits Wareham Police Officer Christopher Smith, who often saw her on the water, for making her aware of the challenge. After some research, she said the group's mission resonated with her personally. It provides housing to children and their families who go to Boston for pediatric cancer treatment.

“When my brother was in a bad car accident we almost lost him,” she said. “Your life stands still. Christopher’s Haven gives families a place to stay when their children need treatment. There are great people in this world who understand the sudden life changes you make when someone you love needs medical help.”

Her boyfriend James Tello, a Swifts Beach native, encouraged her to take part in the challenge. She credits him with sparking her interest in paddleboarding.

Two years ago, he bought McCrillis her first paddleboard as a birthday present.

“I got on and said, ‘wow, this is different,” she said. “My birthday is in June and from then on I wouldn’t stop, I couldn’t stop.”

When winter arrived she didn’t slow down and purchased a wet suit to stay warm. For safety, she lets friends and family know when and where she'll be paddleboarding in case of an accident.

She often chronicles her trips with a GoPro camera, having purchased one after a few costly accidents.

"I lost three cell phones to the ocean," she said. "I've since learned my lesson."

McCrillis said she’s drawn to paddleboarding because it connects her with the beauty of nature. She recalled one memorable trip where she found herself at the entrance of the Cape Cod Canal.

“I launched from Swifts Beach at sunrise. Sunrise over Little Harbor is absolutely gorgeous,” she said, adding. “I came up to the mouth of the canal from that distance I could see down the canal to the Bourne Bridge. It was breathtaking.”

She said she hopes others will come to appreciate area harbors and rivers and the beauty they have to offer, whether it’s in a kayak, on top of a paddleboard or inside some other watercraft.

“We live in such a beautiful area and people that are on the water regularly will know exactly what I mean when I say it’s stunning,” she said “It makes me feel grateful. Buzzards Bay is gorgeous and I wish people would go out on the water. We should start taking care of the beaches and focus on the nature around us.”

To support help McCrillis raise funds for Christopher’s Haven, click here.