Supply teachers: 'You've got to make the best of it'
Classroom standards could be hit because supply teachers are not given enough opportunity for professional development, a union has warned.
Nearly 10% of school lessons are taught by supply teachers, according to education watchdog Estyn.
Owen Hathway from NUT Cymru said there are concerns that supply teachers aren't being given the training they need.
Supply teachers Catherine Davies and Yasmin Jones told BBC Wales education correspondent Arwyn Jones about the difficulties - sometimes being told last minute they will be needed, with little time to prepare.