This measurements presents a full annual cycle of the CO2 Net Ecosystem Exchange dynamics of a high-arctic tundra area located at the west coast of Svalbard using eddy-covariance flux measurements (Location: Bayelva catchment close to Ny-Ålesund, Svalbard). Applied were a thorough error elimination and subsequent data gap-filling. We found an annual cumulated CO2-budget of close to zero gram carbon per square meter and year, but also a strong seasonal variability.