Biodiversity has a measurement problem. Conventional ecological surveys provide only patchy and incomplete data on just a handful of species. In most places in the world, and particularly in the tropics, we lack the data that’s needed to enable meaningful conservation targets to be set, and for progress in meeting them to be measured. However recent advancements in DNA-based methods are changing the way we monitor the natural world, offering practictioners a robust and cost-effective tool for species detection and identification. Environmental DNA (eDNA) refers to the tiny traces of DNA left by organisms in the environment, particularly in water. It can act as a fingerprint of an entire ecosystem and provide biodiversity data at previously unprecedented scales. A key advantage to this approach is in the ease of field sampling – anyone can take a high quality eDNA sample - meaning we now have a tool we can put in the hands of anyone – including citizen scientists, community members and local stakeholders, promoting local engagement in biodiversity monitoring. Led by Dr Natalie Swan from NatureMetrics, in collaboration with researchers from the Universidad de los Andes, this workshop will offer an introduction to eDNA and its practical applications for biodiversity monitoring and conservation. The session is designed to be accessible to everyone, with no previous experience or knowledge of molecular biology required. We will provide a broad overview of this exciting technology, from sample collection to lab processing, alongside real-world use-cases of eDNA data for improved conservation outcomes. The workshop will include a practical demonstration of aquatic eDNA sample collection using simple kits. Participants will also have the opportunity to collect samples themselves, from the nearby coastline in Cartagena. These collected samples will then be analysed by NatureMetrics and the data shared with workshop participants and the wider ATBC team.