“The use of masks will be mandatory in general from the age of six, even if social distance is maintained,” Education Minister Isabel Celaa told a news conference ahead of schools' reopening next month.
Spain's 17 regional governments, which are responsible for health care and education, have in recent days outlined a patchwork of different measures, leading critics to charge there was a lack of coordination.
The northern region of Cantabria's requirement for children as young as three to wear masks sparked particular controversy.
As well as mask-wearing, pupils will also have to maintain a social distance of 1.5 metres (five feet) from each other, Celaa said, except for young children who will be allowed to mix only with their classmates but not with outsiders.
Other measures include requiring children to wash their hands at least five times a day, regularly ventilating classrooms and taking pupils' temperature.
The goal is for children return to schools instead of having online lessons as they did at the end of the last school term due to the pandemic.
“We aim for all students to be present,” Celaa said.
Spain's schools shut in mid-March when the country imposed a strict three-month lockdown to curb the spread of the virus and have not re-opened since.
New cases are growing at one of the fastest rates in Europe and debate has raged in Spain over how to protect children from infection in schools.
Some parents say they will refuse to send their children back to class because they fear it won't be safe.
The number of confirmed cases of Covid-19 in Spain, a nation of around 47 million people, surpassed 400,000 this week. Nearly 29,000 people have died, one of the world's highest tolls.
Against this backdrop, local authorities have toughened measures to curb the spread of the virus. Madrid city hall announced Thursday that public swimming pools would close on September 1st and parks will be closed at night.
The Balearic Islands in the Mediterranean, which include holiday hotspots Ibiza and Mallorca, announced Wednesday that beaches would be shut at night.
With nightclubs and bars closed across Spain, many young people have taken to gathering and drinking in parks and on beaches at night.
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