He says others on the same flight ''probably'' went through in the same way. When he eventually realised his mistake, and that not having an entry visa could cause problems leaving Phuket, he sought help.
The man, who prefers to remain anonymous, says that his Phuket. resort was able to help him to rectify the situation.
The alleged security breach throws into question the ability of staff to cope with an excessive number of passengers passing through the airport, coming and going.
Delays in processing are being exacerbated by high-season crowds. The prospect is that endurance and patience will be stretched even further as temporary measures are take to cope with ever-increasing departures and arrivals before the enlarged airport opens in November 2014.
The man's allegations cast doubts about the efficiency of the expansion, which will require more passengers to be transferred to the old terminal by coach after alighting from flights on the tarmac.
That's what the man says happened last week on his AirAsia flight from Kuala Lumpur.
''I was among the last off,'' he said. ''I think we must have been taken to the luggage collection area, where I picked up my bags and walked out.
''The assumption may have been made that we'd perhaps been checked in Bangkok. I suspect there were others like me who entered Phuket without being checked and without entry visa stamps.''
More tarmac-and-coach passengers are planned to enable the Phuket airport to cope during the expansion.
Where it has been discovered that people have entered the secure zone at airports without clearance in the US and Australia, entire airports have been called to a stop, with passengers even forced to leave aircraft and go through security procedures a second time.
The tally of arrivals and departures at Phuket airport is expected to top eight million in 2011 - vastly exceeding the official capacity of 6.5 million.