Illegal trade in wildlife, illegal logging and timber trading, unregulated fishing, illegal coral harvesting, as well as the illicit trade of waste and smuggling of ozone-depleting substances are, along with other environmental crimes, detrimentally affecting the quality of air, water, and soil, threatening the survival of fauna and flora, causing irreparable damage to our planet, along with placing a heavy burden on both human health and the economic livelihood of billions of people across the globe. However, despite the nascent global awareness of environmental crimes, this area of scientific inquiry requires further investigation by means of rigorous methods to produce sound empirical knowledge that can inform law enforcement activities and criminal justice systems, and advise policy makers. More specifically, several scholars have highlighted the need to produce new solid empirical research on environmental crimes, and recommended utilizing quantitative methods that have hitherto been neglected in this field (Lynch et al., 2017; Lynch & Pires, 2019; Nobles, 2019). The special issue New Quantitative and Qualitative Methods to Investigate Environmental Crimes seeks to improve extant understanding of environmental crimes, advocate for the use of new methods through which to study this topic, and enhance the preventive measures to combat these crimes. I am pleased to introduce this special issue that comprises expert contributions from multiple countries (i.e., Australia, Italy, Sweden, the United States, and the United Kingdom). The articles included in this issue employ different methodological approaches (i.e., quantitative, qualitative, and mixed-methods) to analyze several types of environmental crime in different offline and online contexts around the world (e.g., the illegal harvesting of live corals in Indonesia and Fiji, environmental crimes in protected areas in Cambodia, online illegal trade in endangered plants, and illicit waste trafficking at the global level). Moreover, they present innovative methodological solutions to the study of environmental crimes and guide future researchers in how to construct databases to quantitatively investigate corporate environmental crimes. The first article in this special issue introduces the use of counter-mapping and activist tools as both a new method through which to investigate environmental crimes and as a means to quantify and demonstrate environmental harm in Australia (Barnes & White, 2020). The second article applies risk terrain modeling (RTM) to study fauna and flora-related illegal activities (e.g., illegal logging, flora and fauna poaching) in 939705C CJXXX10.