<p>Local governments are at the forefront of climate action. Responsible for regulating land use and development, they influence greenhouse gas emissions and climate resilience. There is limited research exploring integration and mainstreaming of adaptation and mitigation actions across whole built environment policy portfolios, or comparing local government contexts, e.g., urban vs rural. We developed an approach to assess integration of adaptation and mitigation actions across policy portfolios and applied it to policy portfolios of three diverse local government areas in Victoria, Australia: the City of Melbourne, the City of Greater Geelong, and the Wellington Shire Council. We find that while climate change adaptation and mitigation actions are integrated, they are not mainstreamed into the built environment policy instrument portfolios. Wellington, a rural local government, has half the number of policy instruments of the others investigated, resulting in fewer climate actions across its policy portfolio. These scalar challenges should be addressed in climate planning.</p>