The number of Clare children who are being educated in so-called super-sized classes of at least 30 pupils has soared by a quarter in the past five years.
A Clare FM investigation, outlines which schools are being hit hardest by overcrowding.
The data used for this investigation relates to the ongoing school year, and comes from the Department of Education.
It had already been known that 3260 children here were in classes of at least 30 kids, a figure which has actually fallen from 2015.
However, when compared with just five years ago, this figure has jumped by over 650, a surge of 25%.
Just under 400 students are in classes with at least 34 other classmates – the OECD says the average class size in most developed countries is around 21.
The total number of pupils has also increased in the same timeframe, by a slightly smaller number, suggesting there has not been enough investment in school facilities or staffing levels to keep pace with this growth.
The data, available on a school-by-school level, shows at least 100 kids in super-sized classes in schools in Clonlara, Cratloe, Sixmilebridge, Parteen, Clarecastle, Knockanean, Tulla and Quin, as well as in some schools in Ennis and Shannon.
