‘Fairness’ is veiled with multiple and competing interpretations. Standard Setting Organisations, non-governmental organisations and carbon market actors have introduced fairness notions into the carbon market in an attempt to charter, standardise and communicate alternative approaches for carbon credits produced in smallholder and rural settings in the global South. Propositions that carbon credits can be ‘fair’ are contentious, warranting careful analysis. Using an action-oriented case study approach, I explore Fairtrade International’s attempts to collaboratively develop the Fairtrade Climate Standard and examine its relevance within carbon programmes in Kenya. Multi-sited ethnographic observations and interviews, in Kenya and within various forums for deliberating the standard, are combined with specific tools designed to open-up inputs and enhance reflection amongst contributors to the standard. A Q study reveals three empirical perspectives on fairness in carbon projects, held amongst stakeholders in the standard-setting process. These diverge regarding what would be fair for whom, and mechanisms for achieving it, and not all notions are incorporated into the standard. Critical analysis of the standard-setting process against the benchmark of Fairtrade International’s participatory governance approach illustrates process design features facilitating participatory collaboration and the limits to participatory governance in practice. I develop a heuristic to discuss how the most contentious topics were shaped by the initiators’ ambitions, shared and mutually incompatible interests amongst stakeholders, and dynamics of protectionism. Using a Theory of Change approach I unpack specific mechanisms believed to lead to fairer outcomes and explore associated assumptions and evidence-bases. Key Fairtrade concepts- ‘producers’, ‘organisations’, and transfer between external actors and Producer Organisations; are clouded by mixed evidence. This predicates future monitoring, evaluation and critical assessment of the standard once in operation. Finally I provide practical insights on doing collaborative action-oriented PhD research and make recommendations for researcher engagement in standard-setting processes and opportunities for enhancing deliberation and reflection.