He was among the three people who drowned at the dam including two men.
According to Kwale County Commissioner Evans Achok, search and rescue operations are ongoing to retrieve the bodies.
“The two men had gone to rescue the child who had drowned but unfortunately they also drowned. The body of the child has been retrieved after it was found floating earlier today,” Achok said.
Police have launched investigation.
The incident follows similar deaths of two brothers who drowned in a dam last month in Naivasha. In a separate incident in Laikipia, three boys drowned in an abandoned quarry that was filled with water in September.