Addressing sustainability and low carbon objectives calls for radical departures from existing socio-technical trajectories. The substantial implementation gap between sustainability objectives and current unsustainable paths justifies a continued search for more ambitious system transformations and clarity as to how they can be realised. The aim of this article is to unpack the feasibility of such sustainability transitions pathways (STPs), by identifying the analytical dimensions that need to be considered to address challenges for transitions governance and specifying how they can inform comprehensive evaluation efforts. We aim to offer practical examples of how multiple forms of knowledge can be mobilised to support strategic decision-making, and so complement traditional modelling-based scenario tools. We base our evaluation of STPs on a broad understanding of feasibility and elaborate a frame to mobilise what we see as three 'facets' of STPs: representations for exploring sustainability transitions potentials, as well as the conditions under which STPs may have greater chances of becoming realised. The resulting evaluation frame allow us to generate specific prescriptions about STPs feasibility that can focus interdisciplinary research on the relevance of mobilising a plurality of forms of knowledge in evaluation efforts, a more detailed understanding of the potential of a given solution or pathway, and more detailed assessment of different key dimensions. We end by discussing how the notion of STPs feasibility can help open up decision making processes and what tangible types of interventions are relevant.