The data set contains methane (CH4) diffusion fluxes from three locations at Lake Neusiedl in Austria, measured weekly from late March to mid-July 2021: Channel (CH), Reed belt (RB), and Open water/Lake (OW). Fluxes are expressed daily. Format of datset: CSV Temporal interval: daily Temporal coverage: March - July 2021 Coordinates: Lat. 47.769°N, Long. 16.758°E, 116 m asl The data set corresponding to the publication: Baur, P.A.; Henry Pinilla, D.; Glatzel, S. (2024): Is ebullition or diffusion more important as methane emission pathway in a shallow subsaline lake? Science of the Total Environment. 912, 169112. https://doi.org/10.1016/j.scitotenv.2023.169112