Early childhood is an important time for building children's affinity with nature and the environment. Early childhood professionals play a crucial role in developing young children's understanding of the natural world. Over the past 50 years, there has been a movement in early childhood education and care contexts to provide young children with the opportunity to learn in natural surroundings such as forest schools and nature kindergartens. This research, occurred in four bush kinders, an Australian example of nature-based, early years education influenced by the forest school approach to education. In this paper we interrogate key ideas concerning environmental education, drawing on seminal empirical research, guiding curriculum documents such as Australia's Early Years Learning Framework and government policy documents to build understandings of how children's play can be observed by educators who can then support the children to develop their understandings of the natural world around them. Through ethnography, a methodology that uses both participation and observation of research participants, it became apparent that young children's play-based learning offers opportunities for development of understandings of the environment. Applying a recent definition of environmental education from the US Environmental Protection Authority (2022), we analysed four vignettes which provide examples of educators and children's interactions supporting children to build an affinity with nature observed during the research. This research's implications are novel when considering the relatively new bush kinder approach to early childhood education as the findings remind us of the benefits of bush kinders in generating opportunities for young children's environmental education.