Obtaining sediment samples in unconsolidated sediment presents many challenges. The locale substrate can be soft, penetration of the sediment may be limited, preservation of the sedimentary fabric may be incomplete, and extraction of the sample may be difficult. Some of these issues are overcome with vibracore or suction-core techniques. Vibracoring requires heavy, bulky, and relatively expensive equipment which is costly to ship to the remote field-study locations and difficult to use in muddy settings such as muddy tidal flats or coastal marshes. The Van der Staay suction corer (Van de Meene et al. 1979) is cost-effective and fixes logistical problems, but sample extraction has to be done in the field. The TESS-1 suction corer (Mendez et al. 2003) was designed on the basis of the Van der Staay suction corer and allows recovering intact sediment samples for further laboratory analysis, but it requires custom machinery with more man-hours and uses small-diameter core tubes with a high possibility of disturbance of sedimentary structures in unconsolidated and waterlogged deposits. Here we present a new removable-cap suction corer that is inexpensive to construct, light in weight, highly portable, and can be designed to extract any core diameter. The corer can be used for coarse- and fine-grained wet sediments (tidal flats, riverine and estuarine bars, coastal marshes) and shallow subaqueous environments (lakes, rivers, shallow shoreface).