The trio, Jaafar Ali, Hussain Mansur and Mustafa Abdulkarim, had been charged of attempting to kill three policemen "with premeditation" on February 16, in the Shiite village of Karzakan, southwest of Manama.
The public prosecution had also accused the men of "possessing homemade shotguns, as well as employing violence against police, and participating in an unauthorised protest."
They opened fire on police as security forces were dispersing a protest in the Shiite village, the prosecution said.
Home to the US Fifth Fleet and strategically situated across the Gulf from Iran, Bahrain still sees sporadic Shiite-led demonstrations, mostly outside the capital Manama.
According to the International Federation for Human Rights, around 80 people have been killed in Bahrain since the violence first broke out in 2011.
