The dataset details global positioning system (GPS) locations recorded for survey quadrats at six UK saltmarsh sites. Three of the sites were in Morecambe Bay, North West England and three of the sites were in Essex, South East England, each of these sites consisted of a salt marsh area and adjacent mudflat area. Each site comprised 22 quadrats on the unvegetated mudflat and 22 quadrats on the salt marsh. The locations indicated by this dataset correspond to the south-east corner of the quadrats which were 1m square and oriented with their sides aligned North-South and East-West. We combined spatial data relating to the environs of the study sites from a number of sources (Ordnance Survey Digital Terrain Models, Ordnance Survey Boundary Line, Environment Agency Saltmarsh Extents, Natural England Priority Habitat Inventory). These were rasterised and quadrat values were extracted on a pointwise basis for elevation and proximity (distance to creek, habitat edge and high water mark). Tidal height was calculated with reference to the relevant Tidal Gauge and Admiralty Standard Port information. This data was derived as part of Coastal Biodiversity and Ecosystem Service Sustainability (CBESS): NE/J015644/1. The project was funded with support from the Biodiversity and Ecosystem Service Sustainability (BESS) programme. BESS is a six-year programme (2011-2017) funded by the UK Natural Environment Research Council (NERC) and the Biotechnology and Biological Sciences Research Council (BBSRC) as part of the UK's Living with Environmental Change (LWEC) programme. Full details about this dataset can be found at https://doi.org/10.5285/78a2cab5-dca5-411b-ac5b-c2c080928b1d