Climate change risks to the coast and coastal developments have been well-documented. In spite of these warnings, new coastal developments are still proposed and built. Australian research has demonstrated how State-level planning documents fail to incorporate recent sea-level rise projections, with researchers demanding more responsiveness to coastal science from planners, policy-makers and developers. This paper takes an alternative approach to the science, planning and coastal development nexus by developing a relational understanding of the barriers to the uptake of science into coastal development decisions. Drawing on qualitative interview material from two recent and non-routine South Australian cases where sea-level rise (SLR) science was contested, and inspiration from actor-network theory's concepts of obligatory passage points, translation, intermediaries and mediators, this research foregrounds the malleability of scientific knowledge and planning protocols. We find that skilful social actors negotiate and re-frame science and planning; clear scientific recommendations can be subsumed to planning process, while clear planning process creates internecine disputes between nomothetic and idiographic science. An implication of this analysis is that the broad narrative of a lack of scientific uptake into coastal development needs to be sensitized to how science and planning interact in practice to legitimate decisions.