A 19-year-old Slovakian was caught at the airport on Thursday evening carrying 800 grams of heroin, the police said.
They said the teenager travelled to Malta on a direct flight from Brussels.
A search by Customs officers and the police yielded 80 capsules, which were allegedly found in the luggage and inside his body.
The police said the suspect was expected to be arraigned and accused of conspiring to commit a crime and of drug importation and possession.
Duty Magistrate Joseph Apap Bologna has opened an inquiry.