Ecosystem-based adaptation (EbA) and its sister community-based adaptation (CBA) have gained traction over recent years, and policy-makers and planners are increasingly promoting ‘integrated’ EbA and CBA approaches. Improved learning from older natural resource management disciplines such as community-based natural resource management (CBNRM), however, could help inform EbA and CBA practice and policy-making. This viewpoint describes key lessons from CBNRM that EbA and CBA should address as they mature, including the need for EbA and CBA to ensure: communities are central to planning; the institutional, governance and policy context of initiatives is addressed; and, incentives and the need for better evidence of effectiveness is considered. The viewpoint argues that opportunities for scaling up EbA and CBA through mainstreaming and also replication and diversification to other sectors need exploring to reach the millions of poor people facing a climate change-constrained future. This is particularly important for the world’s poorest people who are worst hit by climate change and also disproportionately reliant on ecosystems and their services.