Tore Gulaker, 62, from Oslo, was found lying on his bed with an oxygen mask on his face. Kusondharm Phuket Foundation staff said they believed he had been dead for about 12 hours.
His body was taken to Patong Hospital for autopsy. Foul play is not suspected.
Mr Gulaker was one of three foreigners who died in Phuket over the weekend. See earlier stories here and here.
