Little Kongpob “Nong Korya” Cherket, disappeared on Thursday evening (April 10) from the family home in a work camp in Rawai, where his parents have a store.
Police said his parents had left him with his grandmother. He had last been seen playing with other children in the camp shortly before sundown.
The child was found in a pond in Nai Harn by local people who called the police.
Police believe the child drowned but the body has sent for autopsy to confirm this.
It is not clear yet whether his disappearance and death are being treated as suspicious.
Earlier this month a four-year-old boy was rescued from a couple who had abducted him, also from a work camp, and were about to take him to Bangkok.
At the beginning of December last year a little girl in Chalong, Nong Dear, disappeared. A body was found two weeks later, a kilometre away, and was confirmed through DNA analysis to be that of the missing child. That death is being investigated.