The Boreal Ecosystem Research and Monitoring Sites (BERMS) are a network of flux tower research sites located near the southern boundary of the Boreal Plains Ecozone in Saskatchewan, Canada. This network includes four principal sites that characterize the region’s dominant vegetation types: mature trembling aspen (Old Aspen, OA, 1997–2017), mature black spruce (Old Black Spruce, OBS, 1997–present), mature jack pine (Old Jack Pine, OJP, 1997–present), and a minerotrophic patterned fen (Fen, 2002–present). The dataset reported here include continuous long-term records of site meteorological variables (air temperature, humidity, barometric pressure, precipitation, wind speed and direction), vertical profiles of soil temperature and volumetric water content, surface energy balance components (soil and biomass heat fluxes, photosynthetic heat flux, and eddy covariance-derived latent and sensible heat fluxes), and carbon fluxes (net ecosystem production, gross primary productivity, and ecosystem respiration). The strengths of the data set are its length and completeness, spanning up to 27 years; the care given to the measurement of net radiation and the minor surface energy balance terms; the care given to the measurement of precipitation and other hydrologic variables; and the proximity of the sites, which enables inter-site comparisons of the responses of the carbon and water balances to climatic controls. The data are available at <a href="https://doi.org/10.20383/103.01318" target="_blank" rel="noopener">https://doi.org/10.20383/103.01318</a> (Helgason et al., 2024).