Concerns regarding the impacts of non-native species due to their transport and release in ship ballast water have resulted in agreements and regulatory requirements being implemented around the world (e.g. International Maritime Organization [IMO] Ballast Water Management Convention [BWMC], 2004; US Coast Guard [USCG], 2012; California State Lands Commission [CSLC], 2018). Consequently, effective and reliable monitoring for ship compliance with ballast water discharge standards is now critical to achieve the regulatory goal of minimizing the risk of invasive species introductions. A variety of ballast water compliance monitoring devices (CMDs) have been developed. This includes various sensors, instruments, kits, methods, and assays that have been designed to assess compliance with ballast water discharge standards and requirements. Additionally, several novel CMD approaches are also currently being explored. However, rigorous, transparent and standardized verification testing is needed for these devices to be adopted and implemented globally, by multiple administrations (i.e. countries, governments, or jurisdictions) to enforce compliance monitoring. Otherwise, CMD performance, data quality, and uncertainties will remain unknown. To address this need, this protocol has been developed by a subgroup of the ICES/Intergovernmental Oceanographic Commission (IOC)/IMO Working Group on Ballast and other Ship Vectors (WGBOSV) to serve as a standardized framework for the verification testing of CMDs.