Police in Surat Thani have found many “visitors” who tried to smuggle suitcases containing cannabis out of the country as over the past four days they have arrested 13 foreign “tourists” with cannabis that would have a total market price of 75 million baht overseas.

Police said on Sunday that authorities arrested four British men at Samui airport on Saturday with 131 kilogrammes of dried cannabis buds in total before they took a flight to Singapore.

Over the past four days, police seized 375kg of cannabis from 22 bags of 13 such “tourists” at Samui airport. If the cannabis was smuggled out successfully, its overseas market price would be 200,000 baht per kilogramme. The seized cannabis could have sold for about 75 million baht in total.

Eight of nine foreigners who were earlier arrested for smuggling cannabis at Samui airport were destined for Singapore and the other wanted to leave for Hong Kong. Their planned final destinations were Britain, Germany and Singapore. The Koh Samui Provincial Court sentenced them to four months in jail.

On Sunday police said the cannabis-smuggling ring by bogus tourists might include a suitcase that a Surat Thani couple mistakenly took from the southern province while joining a tour group to Japan recently.

The bag was opened in Japan and officials found 24kg of dried cannabis inside.

The suitcase actually belonged to a 51-year-old British man identified as Mark Barlow.

Mr Barlow arrived in Thailand at Suvarnabhumi airport on March 6. Without visiting any tourist attractions in Thailand, he left Surat Thani airport last Thursday and left the country on the following day for South Korea.