The Center for Subsurface Sensing and Imaging Systems (CenSSIS), a multi-institutional ERC among Northeastern University, Boston University, University of Puerto Rico-Mayagüez, and Rensselaer Polytechnic Institute (EEC-9986821), with strategic affiliates Brigham and Women’s Hospital, Massachusetts General Hospital, Lawrence Livermore National Laboratory and Woods Hole Oceanographic Institution, is developing a set of subsurface imaging experimental testbeds for the development, testing, and verification of subsurface imaging strategies. These testbeds will be available to CenSSIS researchers and others, and testbed data will be the basis of algorithm competitions for the subsurface sensing and imaging community as a whole. The testbeds are SoilBED, focusing on imaging underground, MedBED for medical imaging, BioBED for subsurface biological microscopies of the interior of cells or collections of cells, and SeaBED for imaging underwater. The value of ERC investment in existing testbeds and the Engineered System is approximately $750,000. SoilBED will consist of outdoor and indoor facilities for ground-penetrating radar (GPR), electro-magnetic induction (EMI), infrared, and acoustic sensing. MedBED includes ultrasound and optical multisensor facilities for imaging in strongly scattering, tissue-mimicking media. BioBED has equipment to demonstrate proof-of-principle of three-dimensional biological imaging by quadrature tomographic microscopy (QTM). The SeaBED implementation focuses on optical multispectral imaging of the near-surface ocean environment.