A ban on wearing the burqa and the niqab in public places came into force in Belgium on Saturday, local media reported.
Offenders will face a possible prison term of up to seven days and a fine of 137.50 euro.
The ban was imposed on the grounds the wearer is not fully identifiable and therefore could be a threat to public security.
Supporters of the law believe it will help the fight against terrorism and also give more rights to Muslim women.
About 270 Muslim women wear the burqa in Belgium according to local media. Two women filed complaints to the Belgian Constitutional Court on Friday, demanding the ban be rescinded.
France was the first European Union country to prohibit women from wearing full-face Islamic garments on April 11.
