The cave church St. Georges is a hand‐carved limestone cave church located in Gurat, southwestern France, which likely developed from a hermitic site by the High Middle Ages (1001–1300 AD). Gurat is unique in that few bioarchaeological studies of monastic collections, particularly in France, have been conducted. This research represents the first effort to understand who the people at Gurat were, and where they might have travelled from, by employing strontium isotope analysis. Such data are used to interpret motivations behind hypothesized mobility. Dental and skeletal tissues from 14 individuals excavated at the cave church site were analysed for their strontium isotope ratio via laser ablation multicollector inductively coupled plasma‐mass spectrometry. The 87Sr/86Sr values in human bone samples from Gurat indicate that all individuals likely lived near Gurat for at least the last few years of their lives. 87Sr/86Sr values yielded from tooth enamel samples indicate that during childhood, the Gurat individuals were mobile and originated from a region isotopically dissimilar to Gurat. Mobility into the site of Gurat may be explained by the pilgrimage routes in which traversed Gurat, as well as by the practice of transhumance. Given that two pilgrimage routes passed near the village, Gurat would have been a consistently well‐travelled site for nonlocal Christians during the Middle Ages. It is therefore likely that many travellers passed through the village of Gurat. Additionally, because Cistercian monks practiced transhumance during the medieval period, and many of the Gurat individuals do appear isotopically to have origins from highland regions in France (i.e., the Massif Central), it is possible that these individuals engaged in seasonal migration between highland and lowland regions. Therefore, the data presented here have demonstrated that, through strontium isotope analysis, the Gurat individuals were likely migrants to the Gurat cave church.