The paper explores time measurements and perception of time by the ancient Slavs in the pre-Migration Period and Slavic settlement of Central and Southern Europe. It attempts to reconstruct a year, seasonal, month-like division and naming, as well as lunar and solar time measurement. Moreover, it explores and attempts to reconstruct what were the common Slavic month names that, is before 5th–7th centuries. It also, discusses the issue of adoption of Julian calendar across the Slavdom in the period between the 9th–11th centuries. The research is based on scarce limited written historical records as it explores the times before writing came to the Slavs. Hence to a large degree it relies on abundant ethnographic sources, as well as on linguistics. Therefore, in principle it employs a comparative methodology and often draws from Indo-European examples.