A total of 86.8 kilograms of drugs were confiscated in the Jan.-June period, down 41 percent from 146.9 kg posted a year earlier, according to the data from the Korea Customs Service.
Despite the on-year decline, the agency said the figure is still the second highest in a decade.
By type, the amount of methamphetamine confiscated fell 28 percent on-year to reach 43.1 kg during the six-month period.
Cannabis detected also decreased a whopping 48 percent to 9.8 kg. Smuggled cocaine, on the other hand, jumped 62 percent to 13.2 kg, the customs agency said.
The customs office claimed Chinese smugglers from Taiwan and Southeast Asian countries have been making attempts to sneak methamphetamine into the country since last year.
Shipments of methamphetamine via overseas post, apparently sold through social media, tripled on-year to hit 13 kilograms, it added. (Yonhap)