Chalong police were alerted by a local person who noticed that the land appeared to have been freshly dug.
Rawai Municipality staff dug up the spot and found a small wooden box containing the dead baby, baby clothes, disposable diapers, a blanket, and other baby paraphernalia.
Chalong police said the dead baby had some damage to its forehead and there was blood on its face, possibly indicating violence.
The body was taken to the Vachira Phuket Hospital morgue while police try to track down the people who performed the burial.