During raids in April and May, Swedish customs officials confiscated 99.5 kilograms of opium from an apartment in Bromma, a Cadillac belonging to one of those convicted, and in a Shurgard storage facility in Solna.
The drug had been concealed inside hollowed out boards.
Police estimated the street value of the narcotics at 15 million kronor ($2.2 million).
The seizure is Sweden’s largest opium bust ever, and according to police and customs officials, one of the largest in northern Europe.
Last year police confiscated just three kilograms of the drug.
Solna District Court sentenced the two prime suspects, aged 31 and 40 respectively, to ten years in prison. While the 40-year-old is an Iranian citizen, he will not be deported because he has lived in Sweden since he was 16-years-old.
Three other men were also convicted for their role in the crime. A 38-year-old is to serve 4.5 years in prison before being deported, while a 41-year-old received a five year prison sentence.
A 42-year-old who had a minor role in the operation was given a suspended sentence and community service.