This paper aims to provide new insights into the integration of blockchain in supply chain activities by examining them through activity theory. Existing blockchain-based supply chain studies are typically atheoretical, meaning they lack theoretical development. Existing studies that are theoretical in their orientation tend to lean towards predictive theories heavily. We suggest that explanatory theory is more beneficial for studying emerging technology. We propose activity theory to theorise and explain blockchain-mediated supply chain activities. Based on case vignettes, we illustrate how activity theory can drive novel insights. This approach highlights how activity theory can privilege extended or new insights in the study of blockchain and supply chains. Future research steps are discussed.