This paper discusses the first integrated strontium and oxygen isotope ratio results from human remains from Pre- and Protopalatial Crete, spanning the period circa 2500–1750 BCE, with a view to offering a more nuanced understanding of past populations, their diets, potential origins and aspects of their mobility: in particular, the extent to which mobility was part of these people’s lives. Twenty-six human individuals from the site of Sissi were sampled for strontium and oxygen isotope ratio in tooth enamel, while five of them were also analysed for corresponding strontium isotope signatures in bone samples. The human tooth enamel strontium isotope signatures follow a broad distribution that is in overall agreement with the diverse substrate geology reported for the site and its immediate range within a radius of 5 km, as well as with strontium isotope results from snail samples also collected from the broader Sissi region. Strontium data variation can be explained by access to different feeding territories in close proximity to the site and possibly also as a result of variation in the composition of childhood diet, while some short-range immigration cannot be excluded either. In a fashion similar to the strontium data, the human oxygen isotope signatures are also consistent with a provenance from within the island. Isotope data variation and the inferred maximization of the exploitation of arable land to extend the agricultural resource base is largely in tune with contemporary socio-economic developments, settlement nucleation and population growth on Crete towards the late Prepalatial period. Use of multiple production zones by the people at Sissi may also be seen as a buffer against climate instability and vulnerability of coastal sites, while settlement nucleation is supported by evidence for the abandonment of contemporary sites in the bay of Malia with the exception of Sissi and Malia. Based on these data we conclude that mobility was part of the life of people at Sissi. They were either moving as part of their daily routine to exploit food resources, or in relation to settlement nucleation with some of them having moved to Sissi from nearby sites. It is also possible that people from nearby sites were buried in the Sissi cemetery. Owing to the overlapping strontium and oxygen isotope signatures in the context of this study, it is currently impossible to choose between the above three scenarios.