In the contest of UNESCO’s eight teacher competencies for sustainable development, this survey study aimed to investigate Finnish (n = 190) and Spanish (n = 170) primary school student teachers’ views on competencies related to sustainability education and the ability to act as sustainability educators. The student teachers’ answers to a questionnaire were investigated using qualitative content analysis. The most common competencies that appeared in the answers were strategic thinking, collaboration and integrated problem-solving. Most often, strategic thinking was reflected in responses related to global, regional and local problems. Normative, critical and systems thinking were the rarest competencies, and self-awareness competency was not detected in the student teachers’ answers. In general, only one or two competencies were found in each answer, and no competency at all was found in the majority of the student teachers’ answers. The educational implications of these results and the implications for initial teacher education are discussed.