As local climate adaptation activity increases, so does the number of questions about costs, benefits, financing and the role that economic considerations play in adaptation-related decision-making and policy. Through five cases, covering a range of climate risks and types of adaptation measures, this paper critically examines Swedish project coordinators perceptions of costs and benefits in already-implemented climate adaptation measures. Our study finds that project coordinators make use of different system boundaries - on temporal, geographical and administrative scales - in their cost/benefit evaluations, making the practice of determining adaptation costs arbitrary and hard to compare. We further demonstrate that the project coordinators interpret costs and benefits in a manner that downplays the intangible environmental and social costs and benefits arising from the adaptation measures, despite their own experience of how such measures negatively impact upon social value. The exclusion of social and environmental costs and benefits has severe implications for justice, as it can bias decisions against people and ecosystems that are affected negatively. Based on the findings, we propose three tentative social justice dilemmas in local climate adaptation planning and implementation: 1. Cost and benefit distribution across scales; 2. The identification and valuation of non-market effects; and 3. The equitable allocation of costs and benefits.