A tax on soft drinks is often proposed as a health promotion strategy for reducing their consumption and improving health outcomes. However, little is known about the processes and politics of implementing such taxes. We analysed four different soft drink taxes in Pacific countries and documented the lessons learnt regarding the process of policy agenda-setting and implementation. While local social and political context is critically important in determining policy uptake, these case studies suggest strategies for health promotion practitioners that can help to improve policy uptake and implementation. The case studies reveal interaction between the Ministries of Health, Finance and Revenue at every stage of the policy making process. In regard to agenda-setting, relevance to government fiscal priorities was important in gaining support for soft drink taxes. The active involvement of health policy makers was also important in initiating the policies, and the use of existing taxation mechanisms enabled successful policy implementation. While the earmarking of taxes for health has been widely recommended, the revenue may be redirected as government priorities change. Health promotion practitioners must strategically plan for agenda-setting, development and implementation of intersectoral health-promoting policies by engaging with stakeholders in finance at an early stage to identify priorities and synergies, developing cross-sectoral advocacy coalitions, and basing proposals on existing legislative mechanisms where possible.