The three were on patrol in the village of Bani Jamra when the blast occurred, the Gulf kingdom's interior ministry said in a statement on Twitter posted late yesterday.
It said that the three sustained minor injuries, describing the explosion as a "terrorist" blast and adding that "necessary steps are being taken", without elaborating.
Witnesses said that the blast occurred late yesterday and that security forces swiftly sealed off the village, which lies not far from the capital Manama.
Attacks against security forces have intensified this year.
Two people, including a Jordanian policeman, were killed in the area last week.
It was the first deadly attack on security forces since parliamentary polls in November boycotted by the main Shiite opposition group, which is calling for democratic reforms in the Sunni-ruled kingdom.
The election was the first in the Gulf state since authorities quelled the 2011 protests.
Bahrain, home to the US Navy's Fifth Fleet, remains deeply divided three years after the month-long demonstrations.
Attacks on the security forces have increased this year, with three policemen -- including an Emirati -- killed in a bombing in a Shiite area on March 3.
Another policeman was killed in a bomb blast in a Shiite village in February during protests marking the third anniversary of the failed uprising.
