Courtney Freckleton, best known by his stage name Nines, was charged alongside accomplice Jason Thompson.
Nines was arrested on June 3rd after searches by police at addresses in London and Hertfordshire.
Read this next: Amazon wants the US government to legalise marijuana
28kg of cannabis was imported from Poland and Spain into the UK, the court heard, with boilers used to disguise the substance and smuggle past border checks.
In a joint operation between multiple EU and UK security services, encrypted chat service Encrochat was infiltrated last year — Nines offences are believed to have come to light following searches carried out on the platform.
The rapper has previously served 18 months in jail after being charged for cannabis possession with the intent to supply.
While on trial, he had denied two further counts of conspiracy to supply cocaine and conspiracy to supply cannabis.
Nines was nominated for five MOBO Awards last year, the most of any artist, following the release of his latest album 'Crabs In A Bucket' via XL. He won the Album of the Year and Best Hip Hop Act prizes.
Read this next: Lord Apex is shaping the UK rap underground
Aneesa Ahmed is Mixmag's Digital Intern, follow her on Twitter