The planet is facing a triple crisis from climate change, biodiversity loss, and a pollution crisis. The UK, like any country needs to attract and train the best available talent to become thought leaders to overcome these global challenges. A number of STEM subjects in the UK face challenges with attracting ethnic minority students, but there is a particular gap in our understanding across environmental and marine science subjects. As part of a wider project on diversity in UK environmental and marine science, we have conducted an analysis of approximately 18,000 applications amongst 180 environmental and 88 marine science degrees in the UK between 2019–2021 and have found them to be the least diverse degree subjects for ethnic minority students. Asian students were less likely to be accepted compared to white students on environmental science degrees, with no differences observed for marine science degrees. A survey of 46 UK marine science course/module leaders highlights that they are aware of the problem and believe that this issue is impacting the pipeline of diversity from higher education (HE) institutions to marine/environmental science careers. In this paper, we discuss the impacts of these findings and develop a roadmap to change.