The court of national safety, set up by King Hamad in March, jailed Mahdi Abu Deib and Jalila al-Salman for "calling to forcefully overthrow the regime in union statements" and "promoting hatred to the regime and spreading false news".
The verdicts came a day after the kingdom held by-elections boycotted by the Shia-led opposition to replace 18 Shia MPs who quit the parliament to protest at violence used against demonstrators in February.
The official BNA news agency claimed that the pair used the union to "instigate acts that are considered criminal like calling for sit-ins by teachers, obstructing teaching, holding protests near schools... and calling upon parents not to send their children to school".
Meanwhile BNA reported that in a different case
The court sentenced six men to 15 years in jail after convicting them of chopping off the tongue of an Asian muezzin. Two other men were jailed for 10 years in that case.
Many Asians complained of attacks by Shia who accuse the Al-Khalifa Sunni ruling family of naturalising Asian Sunnis to tip the demographic balance in the country.
Three other people were jailed for three years and a fourth for one year for hiding two wanted persons, BNA reported, and another to three years for failing to report the running over of two police officers and for "inciting hatred against the regime and taking part in public gatherings with the aim of disturbing security".
Authorities said in May that 405 detainees had been referred to courts, while 312 were released.