The school admits children into its nursery class at age 3. When the children reach Year 3, they enter the Junior school, and join with children from Ynyswen Infants, another local school.
Treorchy has two departments, an infants and a junior school, with a long playground separating the buildings. There are around 300 children on roll between the ages of 3 and 11, spread over 10 classes. English is the school's main language, and no pupils speak Welsh as their first language.