In light of recent upward trends in atmospheric carbon dioxide concentration, efforts have turned to methods of sequestering atmospheric carbon into other stable carbon sinks. Enhancing carbon sequestration by natural systems is an effective way of managing carbon sequestration. Due to high productivity and high sedimentation rates, salt marshes are extremely efficient at capturing and storing carbon, and provide the ideal environment for enhancing carbon sequestration rates through the management of livestock grazing, a common use of salt marshes. However, salt marshes are subject to a range of environmental stressors, which can vary considerably over a large spatial scale. It is therefore important to understand the implications of environmental and contextual variability on the use of livestock grazing as a carbon management tool. Twenty-two salt marshes were selected along the coasts of north Wales and north-west England to assess the impact of grazers on above and below-ground carbon stocks and processes in relation to broader contextual variables. The impacts of seasonality on carbon sequestration rates were also assessed by investigating a salt marsh carbon budget over thecourse of one year. Grazing was found to have a negative impact on several above-ground plant characteristics, but no impact on soil carbon stocks or overall carbon sequestration rates. Instead, below-ground processes were explained more by the broader environmental variables and seasonal changes. While this study does not discount the fact that grazing may affect soil carbon stocks on the small-scale, or after initial introduction, it shows that grazing impacts are insignificant relative to broader contextual factors on marshes with well-established grazing regimes.