This chapter focuses on how development co-operation can support scaling up private finance for sustainable ocean economies and scale down and re-orient finance that now flows to ocean practices and activities that are harmful and unsustainable. It starts by quantifying the private finance mobilised for the sustainable ocean economy by official development assistance through leveraging instruments such as guarantees, co-financing schemes, etc. It then identifies a range of new financial instruments – including blue bonds, debt-for-nature swaps, new blue carbon schemes and ocean risks management tools – developed with the support of the development co-operation community. It discusses the current market size of these new instruments, as well as main challenges and opportunities for replicating them and scaling them up. The chapter closes with a set of suggestions for re-focusing financial flows away from unsustainable ocean activities and streamline investment sustainability.