<p>Innovation is viewed as essential for advancing the circular economy, yet we know less about how industrial firms organize the transition toward circular business models through their innovation projects. This paper offers a bottom‑up perspective to the circular business model transition by examining 15 circular economy innovation projects across three Norwegian process industry firms (2021–2024). The analysis shows that projects generate distinct changes in business model elements depending on the circular economy strategy pursued: reduce, recycle, or recover. The projects rely on only three of the nine R strategies, and around half remain closely aligned with linear production, resulting in low levels of circularity. These patterns are shaped by structural and organizational characteristics of the process industry, where capital‑intensive systems and path‑dependent production models constrain more transformative forms of circularity. As a result, the projects function as early‑stage experimentation, introducing foundational but incremental adjustments that mainly target side streams rather than the business model. The study contributes to circular business model research by clarifying how circular economy innovation projects operate as entry points in the early phases of business model development and by identifying the specific business model changes they trigger. The findings offer guidance for firms seeking to strengthen circularity and policymakers aiming to support the circular economy transition in resource‑intensive industries.</p>