SeaBED is a testbed used to collect multiple layers of data from multispectral, hyperspectral and other sensing modalities for the detection and classification of underwater objects. The testbed is composed of three distinct analysis systems: a laboratory set-up, an outdoor tank, and a field site located on a nearby reef in southwest Puerto Rico. Together, these test facilities provide the flexibility and control to acquire fully characterized ground truth information. The main objective of the effort is to develop testing facilities and data sets for researchers to use in assessing the analysis capabilities of subsurface aquatic remote sensing. As such, SeaBED provides controlled environments for examining subsurface spectral behavior as a function of varying illumination conditions, viewing geometry, water optical properties and benthic composition. Additionally, by collecting a comprehensive multi-layer set of spatial and temporal data, the field site offers a system for evaluating analysis techniques under natural environmental conditions.