The UK saltmarsh database of carbon and GHG (greenhouse gas) fluxes was compiled from a systematic literature review conducted using the Web of Science on 11/12/2023 and searches on UK Government organisations and non-government agency websites on 29/02/2024. A total of 8,974 papers were reviewed for carbon accumulation and stocks, GHG fluxes (CO2, CH4 and N2O) and other relevant environment data in natural and restored (i.e. rewetted by managed coastal realignment) saltmarsh habitats applicable to the UK, for incorporation into the database for the potential use in GHG inventory reporting and carbon accounting. Full details about this dataset can be found at https://doi.org/10.5285/a114e2de-bbed-45d2-9af1-372edb4b5025