The project „CLIL as a competence - based teaching approach in subject and foreign language classes“ is the teachers‘ job shadowing mobility project with the purpose of learning. The continuous activity of the gymnasium includes implementation of the formal education programmes (General Education Programme and International Baccalaureate Diploma Programme) and non-formal education, implementation of national and international projects. The enhancement of teachers‘ in-service training is one of the priority areas of the gymnasium, ensuring the improvement of education quality. The gymnasium seeks to make favourable conditions for the teachers‘ in-service and qualification activities and encourages experienced teachers take part in various projects dealing with education quality improvement. It is planned to make favourable conditions to participate in mobilities for 6 teachers of various subjects using the CLIL method in their lessons. Teachers of different subjects will participate in 5 days mobilities in FLORIDA secondary education centre (FLORIDA Secundaria). The mobilities are intended for the teachers having theoretical basis and wanting to apply the knowledge on CLIL in their lessons. Therefore during the job shadowing the principles of practical application of CLIL will be emphasized. During the mobilities the teachers will improve their professional competences (personal benefit for the teachers), which will make a direct impact on the quality of their lessons (benefit for students): the gained didactic knowledge will allow to teach more effectively, using a wider variety of methods, which will have a direct impact on the education quality and learning results. This is a considerable benefit for the school, allowing not only to implement one of the strategic goals of the school, but also improve the quality of teaching.