Rules requiring secondary school pupils to SLOTXO wear masks in class must be scrapped with "immediate effect", the children's commissioner for Wales has said.
Currently children aged over 11 must wear face coverings in Welsh schools, including while in class.
Sally Holland said restrictions on children in schools were "out of sync" with freedoms afforded to adults.
The Welsh government said talks had begun with schools to allow them to decide their own safety rules.
Education Minister Jeremy Miles has said schools and colleges should be allowed to escalate or drop measures, such as wearing face masks and social distancing, according to local case rates.
It does not mean those safety measures - which are currently subject to national guidance - will be totally scrapped.
However, on Monday the minister said he wanted them to "gradually ease", with schools running as normal as possible in the autumn.
Prof Holland said the restrictions on pupils requiring them to wear face masks in classrooms were not in line with current guidance for adults, and needed to end.
"Adults in Wales can sit in a pub with friends from six households, without wearing a face covering, while most of our secondary pupils are required to wear face coverings all day, every day, whilst seated, despite known impacts on their learning," she said. She said if it was not possible to scrap them immediately, then the masks should be scrapped in classrooms by the start of next term.
Prof Holland also called for the end of mass self-isolation requirements, claiming they were detrimental to young people.