Pengtrau Chen, 26, was staying with his wife at the Casuarina Resort.
It is believed he had been snokelling off Klong Hin beach.
Photographs taken at the scene show him still wearing a facemask, pushed up to his forehead.
Deaths among Chinese tourists holidaying on Phuket and in Krabi are not uncommon.
Details of precisely what happened today have yet to emerge.
His body is at the small Lanta Hospital.