This research was conducted to examine the views of preschool teachers regarding out-of-school learning environments for mathematics activities and their usage of these environments. The research was conducted out using a phenomenological design, one of the qualitative research methods. The study group consisted of 42 preschool teachers working in preschool education institutions affiliated with the Ministry of National Education, determined on a voluntary basis. The research data were collected through a semi-structured interview form created by the researchers. The analysis of the obtained data was done by content analysis method. The research results revealed that preschool teachers have sufficient knowledge about out-of-school learning environments where mathematics activities can be implemented and that they use various out-of-school learning environments. The preschool teachers participating in the research stated that they found out-of-school learning environments beneficial for math activities but faced various difficulties during the implementation process. Positive teacher opinions were found regarding out-of-school learning environments increasing children's interest in mathematics and developing their problem-solving skills. It was revealed that teachers use these environments most often for reasons such as connecting with daily life (making it concrete), learning by doing and experiencing, permanent learning, and being engaging.