An elderly man drowned while swimming in the waters off Brooklyn’s Brighton Beach, police said Monday.

A passerby saw the 70-year-old struggling shortly before noon Sunday. The good Samaritan pulled the man from the water and brought him to Riegelmann Boardwalk near Brighton 4th Street, police said.

Cops and medics arrived to find the victim unconscious on the pedestrian pathway. EMS rushed him to Coney Island Hospital, but he could not be saved.

Police do not suspect any criminality and said there were no obvious signs of trauma to the man’s body. The city medical examiner will determine his official cause of death.