On November 29th 2018, during the 2018 SERDP & ESTCP Symposium, fifty members of the Munitions Response community gathered at the Washington Hilton for this Underwater UXO Standardized Demonstration Sites workshop. The objectives of this workshop were to establish the requirements, framework, protocols, responsibilities, and time lines for development of a series of test beds used to test, evaluate, and demonstrate acoustic, magnetic, EMI, and optical systems designed to detect and classify underwater UXO. Potential systems include various combinations of commercially available sensors and platforms, systems developed for mine hunting (MCM) for the Navy, modifications of EMI and magnetic systems developed for terrestrial UXO remediation, and purpose-built systems developed with SERDP/ESTCP funding. Detailed information on the division of responsibilities among demonstration site managers, remediation system developers, and the ESTCP Program Office related to the design, construction, operation, maintenance, and use of underwater test beds can be found in the Workshop Report.