Prisoners called their families from inside the prison to alert them to the crackdown, Sayed al-Muhafada of the Bahrain Center for Human Rights said.
The rioting occurred in Bahrain's Dry Dock prison on the island of Muharraq, northeast of the capital, Manama, the group said in a statement, adding that the ward at the center of the revolt houses many anti-government activists and human rights defenders waiting to be tried on terrorism charges.
The Interior Ministry announced that order had been restored following the riots, saying on their official twitter feed that prisoners had tried to "break the doors and police interfered and restored order."
Bahrain has seen over two years of unrest linked to the Shiite majority's demands for a greater say in the affairs of the minority Sunni-ruled kingdom. In recent months, security forces have mostly kept protests away from the center of the capital.
The island nation with a native population of more than 550,000 has been gripped by near nonstop turmoil since February 2011, when Shiites inspired by the Arab Spring wave of revolts began the uprising.