Large freshwater mussels, also known as naiads, are important organisms that provide crucial ecosystem functions and services but are experiencing significant declines across Europe. To ensure effective conservation, it is essential to have a well-coordinated monitoring scheme. Therefore, we analyzed the functioning of naiad monitoring systems in 31 European countries. Monitoring of naiad populations is not coordinated in Europe, is largely unrelated to monitoring of water quality or host fish species, and receives irregular funding. Raw data on monitored species are typically unavailable, which hampers independent and/or large-scale analyses. The quality of EU monitoring schemes according to Article 17 of the Habitats Directive is poor for the most threatened species. To improve this, a new scheme is recommended with raw data stored in publicly available repositories to enable instant analysis and rapid, appropriate, evidence-based responses that can support the conservation of this imperilled taxon.