Lambertian-equivalent hyperspectral reflectance measurements were completed on 26 June 2019 on the east shore of the Spuikom lagoon in Ostend, Belgium between 10:00 – 12:00 local time (UTC + 2 hrs) under natural sunlight. An ASD spectroradiometer covering the wavelength ranges 350 nm to 2500 nm was operated in reflectance mode and was fitted with an 8° field-of-view lens. Relative reflectance was derived by white referencing using the 99% white Lambertian plaque, the calibration reflectance factor of the panel is also provided with this dataset. Each relative reflectance measurement over a sample was taken as an average of 30 continuous scans. The measurement sequence involved a white reference measurement followed by a sequence of 10 random point sampling of the sample and then another white reference. We did concrete bricks near the dry land target that had a pattern of faded red and gray bricks. We did first 10 over gray and the second 10 over red bricks. We measured over the asphalt in the road next to the sail club and adjacent to the dry target. The plastic targets included small boats, polyethylene terephthalate (PET) water bottles and low-density polyethylene (LDPE) PMD plastic bags.