Angel swimmer

Kevin Yamada, an angel swimmer at the Swim Across America charity swim between the Boston Harbor Islands

noun - An angel swimmer is an individual competent in lifesaving or a lifeguard who provides safety and support in the water, shore-side, or on safety equipment like kayaks or paddle boards for swimmers or triathletes in open bodies of water during events, triathlons, and open water swimming competitions.

The angel swimmer stayed by the women's side as she was swimming through the surf.