Purpose By drawing on previous research on mechanism-based explanations and business-to-business engagement, the purpose of this study is to identify and define mechanisms that enhance Internet of Things (IoT) engagement. Design/methodology/approach By positioning the study within the paradigm of critical realism (CR), this paper used multiple case study research. This paper applied 12 in-depth, semi-structured interviews, an observation and firm documents as data-gathering tools. Findings This paper argues that the higher-level phenomenon (Institutional logic of the IoT ecosystem) leads to a higher-level outcome (IoT engagement). As lower-level situational mechanisms, this paper found IoT readiness and transparency in the ecosystem. Action-formation mechanisms were acknowledged as communication, availability of an IoT interface, and support. Commitment, trust, satisfaction and software maintenance and updates were recognized as transformational mechanisms. Practical implications The findings will help managers to understand which mechanisms to focus on when forming engagement strategies for onboarding new actors and strengthening relationships with existing actors. Furthermore, this paper suggests considering the IoT readiness of new actors more critically, as this mechanism was found to be the most crucial one for an early stage of engagement in an IoT ecosystem. Originality/value This study helps understand the causal structures behind engagement and enhances the theoretical and practical domain of IoT engagement. In addition, this study demonstrates the value of applying CR for generating knowledge about a phenomenon through causal explanations.