The loss of biodiversity is one of the most urgent global environmental problems of our time. Public education and awareness building is key to successful biodiversity protection. Knowledgeable and skilled student teachers are a key component for the successful implementation of biodiversity education in schools. Yet, little empirical evidence exists on teachers' detailed understanding of biodiversity. This study aimed to assess student teachers' conceptions of the terminology as well as their understanding of the distribution and loss of biodiversity. Data were collected from a qualitative in-depth interview study of student biology teachers from Costa Rica and Germany (n?=?24). Both verbal and visual methods were used to elicit responses. The results show that participants from both countries equated biodiversity with species diversity and had misconceptions about genetic diversity. Costa Rican student teachers seemed to have a more local perspective on biodiversity and unanimously described their local biodiversity as high, and under threat. In contrast, German teachers showed a more global view and were mostly uncertain about the level and threat status of local biodiversity. Prevailing associations explaining the global distribution and loss of biodiversity were heavily based on everyday assumptions, such as the presence/absence of humans, cities, and industries. Additionally, the transnational character of many of the socioeconomic drivers causing biodiversity loss was largely neglected. Although most participants were unfamiliar with the scientific concept of biodiversity hotspots, they implicitly used a naive biodiversity hotspots concept to explain the distribution and loss of global biodiversity. The results are discussed in terms of the educational implications.