AbstractThe transition towards the circular economy—viewed as a holistic solution to meet the sustainable development goals—requires the crucial engagement of the corporate sector, and thereby, radically new business models. Whilst academic literature abounds of tools classifying and categorising circular business models, comparatively little is known in terms of how exactly they look like in the corporate context. Drawing on case studies of small, British circular start‐ups, this article illustrates the characteristics of circular business models and their fit with progressive business models, which are conceptualised as serving nature, future generations, and society, while maintaining financial profitability. This article also highlights how circular business models contribute to competitive advantage and the distinctive challenges met in implementation. As a result, this research contributes to the scant academic literature exploring circular business models implementation, particularly within the context of start‐ups and SMEs.