Salt marshes and, to a lesser extent, tidal flats, attenuate incoming hydrodynamic energy, thus reducing flood and erosion risk in the coastal hinterland. However, marshes are declining in aerial extent both globally and regionally (e.g. the Northwest European region). In order to comprehend why a reduction in salt marsh extent due to marsh edge erosion is occurring, we need to understand the resistance of salt marshes to incoming hydrodynamic energy. This resistance depends on marsh biological, geochemical and geotechnical properties. However, there currently exists no systematic study of marsh geotechnical properties and how these may impact both marsh edge and marsh surface erosion processes (e.g. surface removal, cliff undercutting, gravitational slumping). This has led to an oversimplification of marsh evolution models. Here, we present the initial results of a systematic study of salt marsh and tidal flat geotechnical properties (shear strength, plasticity and particle size) at Tillingham marsh, Essex, UK.