On November 4 2016, the Paris Agreement entered into force. To date, 190 countries have submitted 164 nationally determined contributions (NDCs) outlining their own goals and methods to reduce emissions in common effort to limit global temperature increases this century. In maintaining momentum after Paris and NDC implementation, more onus will be placed on international public finance actors – bilateral aid agencies, export credit agencies, bilateral development banks, multilateral climate funds, and multilateral development bank – scaling up their own flows while using money most effectively to leverage others; coordinating and collaborating on approaches and avoiding duplication; as well as reconciling mandates on climate finance delivery with other mandates on poverty alleviation and the Sustainable Development Goals (SDGs). Optimizing the use of international sources of public climate finance requires recognition of existing and emerging actors’ inherent constraints, the capacity and needs of developing country systems to absorb finance, and a long term view of how circumstances change in uncertain economic and political environments.