Unexploded ordnance (UXO) resulting from military and defense activities remains an issue in underwater areas across the United States. The DoD has identified more than 400 underwater locations containing remnant military munitions from weapons testing and training activities. To address the challenge posed by this threat, the Strategic Environmental Research and Development Program (SERDP) and Environmental Security Technology Certification Program (ESTCP) underwater Munitions Response (MR) program is developing standardized UXO demonstration sites (“testbeds”) to rigorously evaluate technologies that can detect, geolocate, and classify munitions and debris in shallow water (0-35 meter depths). The Sequim Bay testbed in Washington State, operated by the Pacific Northwest National Laboratory (PNNL), is one of several SERDP-ESTCP demonstration sites located in coastal waters.