In three separate incidents, the police seized 75.5 grams of crystal methamphetamine (ya ice), 206 methamphetamine pills (ya bah) and 10 grams of marijuana.
On Monday narcotics police searched a house in Rassada that officers had been watching for some time after receiving a tip-off about drug use at the house.
They arrested Julapetch Boonchoy, 28, and Nethnapa Dejkoth, 32, with the 75 grams of ya ice and 206 ya bah pills, althogether worth close to B300,000 on the street.
Julapetch and Nethnapa were charged with possession of Category 1 drugs with intent to sell.
The other arrests were made at 11pm on Tuesday after an undercover officer paid Wilai Yaondee, 27, B1,000 for half a gram of ya ice, at a meet at a gas station in Patong.
After buying the drugs the officer identified himself and Wilai was arrested on a charge of possession of a Category 1 drug for sale.
Acting on answers to questions they asked Wilai, police then went to a rented room in Nanai Rd in Patong where Kanyaporn Khunthong, 28, and Alessandro Famondi, 38, from Italy, were arrested after being found in possession of 10 grams of marijuana.
They were charged with possession of a Category 5 drug.