Two others people, Parinya Somloi, 33, who allegedly held 0.43 grams, and Sumalee Sankampa, 34, who allegedy held 2.2 grams, were also arrested.
The previous night in Patong, Nigerian Ibenuba Henry Onyinyechukwu was arrested in a similar police sting, this one involving cocaine.
Somkid Kwanngern, 30, was first arrested in an apartment, allegedly with 1.2 grams of cocaine.
He informed on a British man, Curtis Martin Taylor, 32, who was arrested at his apartment on 50 Pi Road, with a small amount of marijuana.
Mr Onyinyechukwu was called to the British man's apartment and allegedly arrived there carrying 5.45 grams of cocaine.