Acquiring writing skills requires an entire academic lifetime but acceptable levels of proficiency should be covered in compulsory education. This research verifies the beginner, intermediate and advanced levels of writing skills in the Spanish education system. It compares both the development of knowledge and the associated difficulties in interviews with 40 students from the even years of primary and secondary education. Descriptive and correlational analyses were made, after coding their statements according to the theoretical model used. They revealed an unexpected stagnation, depending on the levels, with important educational implications.