Grain was the most important food source in Europe during the early modern period (c. 1500–1800). The price level of grain and its volatility played a pivotal role in determining food security and, ultimately, societal and human well-being. Conflicting findings have been reported as to what extent early modern grain price volatility decreased over time. We systematically reassess early modern grain price variability, using 69 annual price series of barley, oats, rye and wheat, and different statistical methods to obtain insights into spatio-temporal changes. Over the entirety of Europe, the different grain types showed a strong price correlation, implying a low level of food security, but the price inter-correlation between grain types decreased over time — indicating an improved level of food security. Grain price volatility significantly decreased over time, especially after c. 1725 and at coastal locations, lessening the risk of food stress and reflecting market improvement from the perspective of consumers. Changes in price volatility closely followed changes in price levels until the mid-seventeenth century, when both started to be increasingly independent of each other, partly owing to less abrupt volatility changes. The largest increase in both price level and volatility is observed during the ‘price revolution’ of the late sixteenth century as well as during the Thirty Years’ War (1618–1648). In general, a high-price–low volatility pattern (and vice versa) is found throughout the early modern period and especially during the seventeenth century. This relationship, however, exhibits a somewhat geographically heterogeneous pattern, although with lower prices but higher volatility predominating in inland regions. To summarise, our results support the assumption that the level of food security improved over time and especially during the eighteenth century, but at the same time reveal considerable differences between grain types, measures considered, and geographical regions. The findings of this study point towards the need for further research on the geographical patterns of grain price variability and the factors explaining them.