The aim of this study is to explore the lived experience of students ( N = 1,282) in general education engaging in collective free improvisation (CFI). Fourteen music teachers implemented a CFI lesson in 69 classes in Flanders (Belgium). Lived experience was measured using a Dutch version of the Flow State Scale for Occupational Tasks. This scale reflects the degree of Sense of Control, Positive Emotional Experience and Absorption by Concentrating. In addition, teachers’ reflections were mapped by means of an online survey. Overall scores on the 3 dimensions of the Flow scale averaged greater than or equal to 5 (7-point Likert scale). Results show a difference in total flow between students who already played an instrument and those who did not. Students who play an instrument score significantly higher on the factor ‘Sense of Control’. Conversely, the flow scores on the factors ‘Absorption by Concentration’ and ‘Positive Emotional Experience’ do not differ between instrumentalists and non-instrumentalists. Given the relatively high flow scores, we conclude that this type of musical engagement can be used for instrumentalists as well as non-instrumentalists. Although CFI was a new experience for the teachers, they indicated to continue using it in the future.