Two of the convicts, one of whom was tried in absentia, were jailed for carrying out a bomb attack targeting police in a Shia village near Manama two years ago, said prosecutor Ahmed al-Hammadi.
The attack had caused damages but left no casualties, he said in a statement carried by the official BNA news agency.
In the second trial the same criminal court jailed a third defendant of opening fire at policemen last year in another Shia town wounding one of them, Hammadi said.
He said that his citizenship would also be revoked.
The defendants were not identified but dozens of Shias have been put on trial and handed lengthy jail terms in the Sunni-ruled kingdom during the past five years.
The criminal court on Monday sentenced three people to life in prison for possessing weapons which they planned to use to carry out a "terrorist" plot.
Bahrain had been shaken by unrest since it quelled a month-long Shia-led uprising demanding reforms which erupted on February 14, 2011.
Tiny but strategic, the kingdom is connected to regional Sunni powerhouse Saudi Arabia by a causeway, lies across the Gulf from Shia Iran and is home to the US Fifth Fleet.
Despite the crackdown on the 2011 uprising, protesters frequently attack police in Shia villages outside the capital Manama.
