Halmstad District Court sentenced the trio to several counts of attempted murder and attempted endangerment of public safety, local media reports.
According to the verdict, the men wrote various posts in encrypted chats in which they tried to get others to commit murders and carry out explosions.
Two men in their 20s were sentenced to six and a half years and five years in prison, respectively, while an 18-year-old was sentenced to four years and two months in prison.
