Conventional coring can be an expensive and cumbersome technique in uncompacted, waterlogged sediments, especially when large numbers of samples are required rapidly and when vehicular access is restricted. The existing Van der Staay suction corer (Van de Meene et al. 1979) solves economic and other problems (chiefly logistical and environmental issues), but sample extraction has to be done in the field. The original purposes of the Van der Staay suction corer were to enable rapid drilling through sand and allow field sampling. It was not designed to recover intact samples for subsequent laboratory analysis. Cores from the new TESS-1 suction corer, however, are encapsulated in the field. The TESS-1 therefore combines the advantages of the original corer with the possibility of taking samples for laboratory analysis. Samples collected using the TESS-1 suction corer show little deformation, allow coring of soft uncompacted mud and retention of sedimentary structures. Problems due to sediment fluidization and movement inside the core pipe are usually minimal. The TESS-1 suction corer can be used in both wetland areas (beach, tidal flats, and marshes) and in shallow subaqueous environments (lakes, rivers, and nearshore subtidal areas).