Bahrain catches fugitives fleeing to Iran on a speedboat
The men were intercepted along with two smugglers after setting off from the island state towards the Iranian coast, the official Bahrain News Agency (BNA) said.
The agency published the names of the men and said that seven had been sentenced to between 10 to 15 years in prison for "terrorism" activities. The eighth one was also wanted on "terrorism charges", it said.
Bahrain frequently employs the charge of terrorism against opponents of the regime.
The men's attempt to cross the 193 kilometre (120 mile) stretch of water to the Iranian coast was planned by two Bahraini fugitives, the agency said.
One of the men has been convicted to life and the other to 10 years in prison, while both had allegedly escaped to Iran before.
The incident follows a jailbreak late on Friday in which 17 prisoners fled al-Hadd jail near the dry dock on the island of Muharraq, east of the capital Manama.
On Saturday security forces recaptured 11 of the inmates, the interior ministry said but gave no indication of whether they were common criminals or political prisoners jailed in a sweeping five-year-old crackdown on dissent among the kingdom's Shia majority.
Bahrain - ruled by a Sunni-dominated royal family - lies across the Gulf from Iran and is home to the US Navy's Fifth Fleet.
Relations between the two neighbours are tense and Manama has repeatedly accused Tehran of interfering in its affairs and inciting violence in the country.
Bahrain has been shaken by unrest since its Sunni minority rulers crushed a month-long uprising demanding reforms and democracy in 2011.
Despite the crackdown, protesters frequently attack police in Shia villages outside the capital Manama.
Bahraini courts have sentenced suspects convicted of violence to long prison sentences, while authorities regularly blame "terrorists" with alleged Iranian backing for stirring up unrest in the country.
Manama denies it discriminates against Bahraini Shias, but members of the community are currently in prison including opposition leader Sheikh Ali Salman.