The importance of teaching a foreign language to preschool children has been recognized by the National Curriculum for Early Childhood and Preschool Education. The teaching methodology for early childhood and preschool FL teaching has not been prescribed in the sense that it favors one specially designed teaching methodology procedure, rather the foreign language is woven into children’s everyday activities (Nacionalni kurikulum za rani i predškolski odgoj i obrazovanje, 2015). Since the usage of the English language has spread to every continent, it is beneficial for children to start learning it from an early age. Also, age is believed to be one of the factors influencing foreign language acquisition, i.e., children are considered more adept at learning foreign languages than adults. One of the important areas of language development, especially in the early childhood is vocabulary, which children can, if appropriate teaching procedures and materials are used, acquire quite easily. Learning that happens "in", "about" and "for" the outside space is referred to as the outdoor curriculum or forest kindergarten. The goal of the forest kindergarten is to help children become more active, confident, creative and to develop critical thinking. In today's world, there is more pollution and destruction of nature, and people in general are becoming alienated from the nature. However, children who experience nature as a calming environment as they grow up are more likely to love and appreciate it in the future. The main objective of this thesis was to gain insight into EFL acquisition of children enrolled in the programs of early EFL acquisition and outdoor curriculum. The sample included 21 children aged four to seven. The first phase of the research was based on the recordings and notes of everyday activities and the children's conversations with the kindergarten teacher. The second phase was the interview with some of the children. There was a total of 11 interviews and participants were aged five to seven. The obtained data were analyzed qualitatively.