The Nelson Bay not-for-profit preschool will open its doors between October 27 and 31 for past students and parents to wander in, have a look and see how much, or little, it has changed in 40 years.

"It is an open invitation," the preschool's Adelaide Rombouts said.

Those interested in heading to Karingal Preschool, at 14 Gowrie Avenue, Nelson Bay, can do so from Monday until Friday, between the hours of 10am and 3pm.