A piston core sampler was adapted for use in shallow water. Nearly 300 cores were taken in the Chesapeake Bay area, the majority of which were in sandy or gravelly sediments. These cores ranged in length from six inches to twenty feet with an average sand core length of six feet and the longest sand-gravel core fifteen feet. The apparatus consists of all upper assembly containing lead drive weights, a coring tube, a reducing coupling, piston, tool steel cutting edge, and a release mechanism modified after that of Hvorslev and Stetson. A rapid method of operation is described which has been found to work efficiently under favorable weather conditions. The length of sand and gravel cores recovered appears to depend upon grain size, water content, and wall friction.