Four youths were apprehended by police after allegedly breaking into a classroom at the Port Lincoln Junior Primary School.
Security and police patrols responded after silent alarms activated at the school grounds about 11.30am on Friday 3 January.
Police caught the four youths running from the scene.
An 11-year-old boy, a 12-year-old boy, a 15-year-old boy and a 15-year-old girl were all arrested and charged with aggravated serious criminal trespass and will be dealt with via the juvenile justice system.
Police are also investigating other damage caused to the school during the holidays, including broken windows.
Police call on local residents living near our schools to keep an extra eye and ear out during school holidays. Anyone who sees any suspicious activity, people or vehicles in or around school grounds, day or night, is urged to ring the police assistance line on 131 444.