Ryder Williams, 16, said he saw the 10-year-old knocked down in ankle-deep water at Seabright Beach on July 25, radioed the emergency and sprinted in with an inflated rescue buoy.
10-foot waves and strong currents driven by hurricanes Fausto and Genevieve made the rescue unusually dangerous; Williams said the child was limp and he had to duck under two or three waves before Aaron Bohnen helped bring him ashore.
California State Parks said lifeguards made 34 rescues and more than 5,000 preventative contacts across the Santa Cruz district on July 25-26, underscoring how severe the surf was that weekend.
The National Weather Service expects hazardous conditions to last through at least 5 p.m. Saturday, and officials urged beachgoers not to attempt rescues, to stay near lifeguard towers and keep children within arm's length.