The circular economy (CE) has gained increasing attention as a means towards sustainable development. Entrepreneurs and small and medium enterprises are regarded as key custodians in the transition to a CE. Opportunity identification is the cornerstone of entrepreneurship and has been extensively studied in traditional venturing; however, research on circular opportunity identification is limited. This paper addresses this gap by exploring (1) how entrepreneurs identify opportunities in the CE, underpinned by an adaptation of a sustainable opportunity identification conceptual model and (2) how CE principles are reflected in the identified opportunities, through the lens of the ReSOLVE CE framework. Nine in-depth interviews were conducted with circular entrepreneurs from three European Union member states with high, medium, and low Resource Efficiency Scoreboard rankings. The findings shed light into the black box of circular opportunity identification and indicate that the ReSOLVE levers constitute a useful framework to advance knowledge on circular entrepreneurship.