Emergency medics declared the death of a foreign worker who fell from a patrol boat at the South Port in the city of Ashdod late Friday night.
The Chinese man lost consciousness shortly after hitting the water, and by the time rescue divers managed to find him he was already dead.
Police opened an investigation into the circumstances of his death.
Paramedic Dan Ben Yishai said: “After missing for several hours he was found without pulse or respiration. We conducted medical tests but he showed no signs of life.”