Bahrain will suspend dine-in services at restaurants and cafes and move public and private schools to remote learning for three weeks to contain the spread of the coronavirus, the health ministry said.
It said it had detected a new variant of coronavirus in a number of cases, without specifying which kind.
The new lockdown measures will come into effect on Sunday.
There has been an uptick in coronavirus cases in the Gulf kingdom since December. The country registered 459 new cases on Wednesday, adding to a total of nearly 100,000 since the start of the pandemic, with 370 deaths.
The small island state has the third highest rate of vaccinations per capita in the world so far, according to the Our World in Data website, which is run by an Oxford University research programme.
Bahrain offers its citizens either the Pfizer/BioNTech vaccine or one manufactured by Chinese state-backed pharmaceutical giant Sinopharm free of charge.
The kingdom also approved the AstraZeneca COVID-19 vaccine on Monday for emergency use.