The aims of the move include improving safeguarding and online safety, focus and learning, mental health and wellbeing, and relationships and social development, the letter said.
It added that each school will implement the approach in line with its own mobile phone policy, and reviews would be held over the course of the 2026–2027 academic year with an eye to possibly extending it to older year groups.
Education Secretary Bridget Phillipson wrote to schools earlier this year encouraging them to follow new guidance that schools be phone-free for the entire day.
Meanwhile, a national petition calling for a clamp down on harmful social media has reached nearly 106,000 signatures.
Produced by the group Smartphone Free Childhood, it wants to delay access to smartphones and social media, to prevent under-16s accessing age-inappropriate online platforms.
