Police were waiting at the Thalang Post Office on Monday (May 14) for Phuket local Suwimol Sampoarat, 44, to come to pick up her parcel.
Police searched the package and found three handbags filled with cocaine, with an estimated street value of B6m.
Suwimol told police she had come to collect the package on behalf of her friend, Sirikorn Pankrajang, 45, a Bangkok local who works in Phuket.
Later that afternoon, police took Sirikorn for questioning at the Thalang Police Station. She admitted the cocaine was sent to her by her Nigerian boyfriend, Kevin David, who was living in Bangkok.
Police are now searching for him and the two Phuket women are being held in police custody.