NSW has banned phones in public high schools. Individual schools decide how to implement the ban. 

Students use lockable pouches to carry their phones with them but not access. Before students enter the school grounds, they lock their phones in the pouches and show a teacher at the school gate.

Once the school bell rings at 3:10pm, students can unlock their pouches at one of the magnetic unlocking stations around the school.

A  2018 independent review into mobile phones in schools resulted in mobiles being banned in NSW primary schools.

It resulted in improved academic outcomes, reduced distractions and a lot more social interaction. 

https://www.abc.net.au/news/2023-10-11/phone-free-schools-hunter-region/102943532