The official Bahrain News Agency quoted Ahmed al-Hammadi, the country's general advocate for terror crime prosecutions, announcing the court's decision.
The report said the five planned terror attacks and received weapons training, as well as had links to Iran's elite Revolutionary Guard.
The report yesterday did not name the five convicted, but said they had regular access to defense lawyers and could appeal the sentence.
It said three were convicted in absentia. It said the two in custody received life sentences.
Bahrain is home to the US 5th Fleet.