Irishman Kieran Moloney knows of at least one other tourist - a woman from Estonia heading for Australia, where she now lives - who was robbed of about $600 on the same bus trip south from Bangkok. He speculates that it happens ''all the time.''
Phuket Deputy Transport chief Wanta Pumararoskon yesterday confirmed Mr Moloney's fears, saying that the night bus route from Bangkok to Surat Thani was a source of growing concern.
''It's a known problem there,'' he said. ''People are safer coming direct to Phuket.''
The 47-year-old Irishman, who has travelled widely over the past 20 years, was shocked when he reached Phuket this week to find he his hand-luggage had been pillaged and and his larger bag - stored with other luggage in the bottom deck of the bus - was also raided.
''As we were lining up for the bus in Bangkok near Khao San Road, the girl selling tickets said 'Keep everything important close to you on the bus.' This should have rung bells,'' Mr Moloney told Phuketwan yesterday.
''I believe this is a scam and probably happening on a regular basis.''
Mr Moloney took a seat near the front of the night bus for Surat Thani and kept his backpack, containing his cash and documents, on the floor close to his legs.
''I was on the inside,'' he said. ''We got off for a break and I took my bag with me. I fell asleep for an hour or two and I woke up in Surat Thani.
''My bag seemed to be a little bit further forward. I looked in the backpack to check and could feel my personal smaller bag inside, so I thought it was all ok.''
His camera and passport were still there. Mr Moloney changed to the Phuket-bound bus and stayed awake through that trip.
Only when he reached his guesthouse accommodation in Phuket City did Mr Moloney, from Cork, discover the cash was missing.
When he checked his large travel bag, he found three new football jumpers, bought as souvenirs and buried at the bottom of the bag, had been taken.
''It happened on the bus from Bangkok to Surat Thani, I am 100 percent sure,'' he said.
When the second bus arrived in Phuket, another passenger off the Surat Thani bus - an Estonian woman who now lives in Australia - asked for his advice about accommodation and headed for the same guesthouse.
''After we'd checked in she said to me, 'By the way, is anything missing from your bags? I think I'm missing some money.'''
It was then that Mr Moloney found his cash - about $300 in euros, dollars and three other currencies - was missing.
''The woman was sitting seven or eight rows behind me, on the other side. For me, it was an inside job. In Myanmar (Burma) I bought three replica football jumpers as souvenirs, and they were gone from the very bottom of my large bag.''
''I know I am not going to get my money back but I want to stop other people from losing their cash,'' he said.
''This will happen tonight, and the night after, and it has probably been happening for months. Police could easily find out what was happening.
''Do the people who run the buses know what's going on? When that girl said 'keep everything tight' I should have realised.''
Mr Moloney said he thought the thieves were unscrewing floor panels to reach the bags.
He had hoped to move next week from Phuket City to Patong to celebrate Christmas and New Year but will now have to consider whether to cut short his trip and head on to Sri Lanka earlier than planned.
''It's disappointing to have it happen in Thailand,'' he said. ''It's just hard to believe people can do that.''
Touts in Khao San Road usually sell bus tickets via Surat Thani as a cheaper alternative to the direct bus to Phuket.
Mr Moloney says he works to travel and enjoyed visits to meet people all over the world.
When he went to City Hall in Phuket City to report the theft, he said his faith was restored. Three people did what they could to help, and took him to the Irish honorary consul.
''To go through your luggage and steal from the very bottom of the bag . . . that's quite unbelievable,'' Mr Moloney said. ''If it happened in Ireland or anywhere in Europe, police would stop this.
''I should be thankful that they left my passport and camera. In 20 years of travelling, this has never happened to me, even on poor local buses in South America.
''You see this beautiful bus, and you don't think people are going to be robbing you as you sleep. If the police were interested, they could solve this problem quickly.''