ISD follows the Dutch school holiday schedule as set by the Dutch Ministry of Education. This includes a summer break of six weeks, an autumn break of one week, a winter break of two weeks, and a spring break of two weeks.

In addition to these holidays, ISD also observes several staff INSET days throughout the year. On these days, teachers focus on training or preparation, and there are no lessons for students.

Special leave for students is generally only allowed under specific circumstances. Permission may be granted by submitting a request for leave of absence, at least two weeks prior to the event. More can be read about this in the school guide.