•First published isotopic tracing of humans in Slovenia.•Baseline measurements on small archaeological animals.•Out of 32 analysed samples a few of the highest/lowest values might be non-local.•Individual with one of the earliest LBA iron objects was very likely a foreigner.•The majority of non-locals can be dated to the very beginning of the EIA period. The cemetery at Dvorišče SAZU in Ljubljana, Slovenia, was in use for a long period, continuously from the Late Bronze Age into the Early Iron Age. More than 300 excavated graves offer a great potential for the analysis and discussion of chronological issues, demography, social inequalities, funeral attires, as well as burial customs within the Late Bronze and Early Iron Age societies. This site was thus chosen as a reference point for our pilot study on mobility and migration in prehistoric Slovenia. The article presents results of the analysis of strontium isotopes (87Sr/86Sr) performed on the 32 cremated petrous part of the temporal bone (pars petrosa) from the cemetery Dvorišče SAZU in Ljubljana and 9 animal bones of small mammals from other sites in the region for baseline information. The stable isotope analysis and the study of mobility in the Late Bronze Age and Early Iron Age presented here is one of the first such investigations involving the osteological material from the south-eastern Alpine region.