The body of Finnish national Jouni Tapani Aulosvuo, 43, was discovered in his South Pattaya apartment when police were summoned by neighbours.
The man was lying on a sofa with a nearby bottle of beer. There was no sign of a struggle or foul play.
Police surmise the Finn may have been a heavy drinker, perhaps with an accompanying serious disease. His corpse was transported to Bangkok for an autopsy. The Finnish embassy has been asked to contact family members.