Education chiefs in Wolverhampton have made the call for secondary school students and staff to take the precaution, despite it not being mandatory.
It comes as they called on youngsters to get regularly tested as they await further guidance on whether the Pfizer vaccine will be rolled out to children.
Government figures have shown more than 1.5 million days of face-to-face teaching have been lost between September and December in the region.
And it is feared pupils' valuable class time could be thrown into jeopardy once again as coronavirus cases continue to rise in areas across the country.
In Wolverhampton, leaders have issued the plea for students to continue wearing masks – despite the requirement being removed as lockdown rules eased.
John Denley, director of public health for Wolverhampton, said: "We support the call for pupils to get tested as they return to school and have been encouraging the whole city of Wolverhampton to make regular rapid testing part of their normal routines.
"In addition to testing, we are encouraging all secondary school students and staff to continue wearing face coverings, just as we did before the half-term break, in order to further reduce the risk of transmission.
"We continue to vaccinate adults across the city and will follow Government guidance around younger people when the time is right."
Leaders at Wolverhampton Council say they reviewed the recommendation over half-term but deemed it necessary due to rising rates in neighbouring areas, primarily led by the Delta variant – formerly known as the Indian variant. The city, in the first half of the summer term, had seen school attendance at its highest level since the pandemic, chiefs say.
In Staffordshire, pleas were made for students to keep getting tested for the virus – even if they have no symptoms – to ensure positive cases can be dealt with quickly, but no guidance has been issued to schools regarding masks use, with schools following Government advice.
Councillor Jonathan Price, cabinet member for education for Staffordshire County Council, said: "We would always encourage regular testing of pupils, and secondary school pupils should be testing themselves twice a week as per the Government's guidelines.
"Asymptomatic testing gives people the peace of mind that they are not carrying the virus or are at risk of passing it on. Testing also helps schools deal with positive cases quickly, closing bubbles if necessary and stopping any further spread of the virus."
And in Dudley, Councillor Nicolas Barlow, cabinet member for health and adult social care, said testing and vaccinating were "crucial" to tackling the pandemic.
He said: "Testing and vaccinating are crucial to tackling this pandemic. We very much echo calls across the country in urging pupils to continue testing from home as they return to class this week. By carrying out twice-weekly testing, positive cases can be picked up early and prevented from spreading, something that is very important as some variants are more transmissible than others. With regard to vaccinating, we will of course be supporting the national policy on the vaccination of under 18 year olds."
Councillor Barlow added: "We are also asking secondary schools to encourage pupils to wear face coverings wherever possible to help reduce the risk of transmission."
In Walsall, Councillor Chris Towe, portfolio holder for education and skills, said schools in the borough were following Government advice and no instructions had been made to change this – as he gave his backing to testing calls.
Meanwhile the UK regulator has approved the use of the Pfizer-BioNTech vaccine in children aged 12 and 15, with the UK's vaccine committee to decide whether children should get the jab.
Councillor Price said he would "urge people to take up the officer of a vaccine when they are called" whilst Mr Denley said the council would "follow Government guidance around younger people when the time is right."