This paper reports carbon, nitrogen, and sulfur stable isotope data obtained from bone collagen of humans from the early medieval cemeteries of Hemmaberg/Gora svete Heme and Oberleiserberg located in Austria. The Hemmaberg/Gora svete Heme cemetery, dating from the 8thto the 11thcentury, comprises 29 graves, from which 15 individuals were analyzed. The Oberleiserberg cemetery, established in the first half of the 11thcentury, includes 71 graves as well as several incidental finds of human bones, from which 75 samples were analyzed. Both cemeteries show comparable δ13C data (mean for Oberleiserberg: –17.5 ± 1.2 ‰, 1σ; mean for Hemmaberg: –16.4 ± 1.6‰, 1σ). However, the δ15N values of individuals from Oberleiserberg (mean: +10.4 ± 1.5‰, 1σ) are slightly higher than those of individuals from Hemmaberg/Gora svete Heme (mean: +8.8 ± 1.1‰,1σ). The δ34S values were only obtained on the individuals from Oberleiserberg, and show a mean value of –0.9 ± 2.0 ‰ (1σ).Beyond the isotopic data presented in this article, we lay the foundations for cooperation between the IsoArcH database (https://isoarch.eu)[1]and the THANADOS (https://thanados.net)[2]project. While IsoArcH primarily stores isotope-related datasets for bioarchaeology, THANADOS stores data on archaeologically and anthropologically researched burials. Moving forward, IsoArcH and THANADOS plan to work closely together to integrate their databases. This collaboration presents a promising opportunity for both projects to pool their resources and knowledge, offering a wealth of information for researchers and the general public who are interested in anthropology and archaeology.