PurposeEducation for Sustainable Development (EDS) has highlighted the need to generate instruments to assess the sustainability competencies of different populations. In this regard, Physical Education (PE) has been recognized as a subject with unique characteristics that allow students to develop competencies that favor sustainability. However, in previous literature, there are no specific instruments to assess the competencies of future Physical Education teachers (PETs). Therefore, this research aims to design and validate an instrument to assess sustainable competencies in future PETs.Design/methodology/approachThis paper shows the validation process of a questionnaire designed ad hoc to measure the future teacher's sustainable competencies. In total, 341 students completed the Physical Education Scale for Sustainable Development in Future Teachers (PESD-FT) questionnaire consisting of 20 items and an eight-point Likert scale. To ensure the relationship of the instrument's items with the sustainable development, the specific targets that compose the 17 Sustainable Development Goals were considered.FindingsThe results showed that the instrument had very high reliability (0.949), excellently fulfilling the validity criteria (0.929). Furthermore, the principal component factor analysis results showed that the PESD-FT comprises three factors, which coincide with the three dimensions of sustainability.Originality/valueIt is concluded that PESD-FT is an instrument that reliably assesses the sustainable competencies of prospective PET and expands the possibilities of PE as a valuable instrument to promote sustainable competencies in an integrated way with PE learning objectives. As such, it can be a robust and valuable measurement tool for proposing effective education for sustainable development policies and programs in initial teacher education for PET.