The Nature Policy Plan Caribbean Netherlands identifies the need to “Evaluate the financial instruments available for nature conservation in the Caribbean Netherlands and make recommendations aimed at guaranteeing a sustainable financial future” as one of its strategic actions. Three preceding studies investigated budget requirements and sustainable funding of nature (MINA 2000, Spergel 2005, Spergel 2014). These studies focused on the potential sources of income to achieve financial sustainability and led amongst others to the establishment of the trust fund. The aim of this study by IMARES is to provide insight in the financial needs to carry out park management tasks based on quantifiable tasks. So, rather than the functional approach of earlier studies, which quantified budget needs based on staffing of the park management organizations, we here introduce a task-based approach to identify budget requirements. In this we used elements of the Netherlands cost standards for nature management ('normenboek') to build an analytical calculation model which quantifies the annual budget requirements and human resources based on quantitative estimates of prices for material and labor. The budget requirements were then used to determine the financial gap between financial needs and income sources. Three financial gaps were identified: 1) the difference in annual budget requirements according to this study and according to an earlier DCNA assessment; 2) the financial gap in the DCNA trust fund required to start generating returns on investment; and 3) the difference between the annual budget requirements according to this study and the current income sources. We recommend parties to use the task-based calculation model as designed in this study for future management and fundraising purposes and to plan and justify the activities and budget requirements of the park management organizations. However, the price, cost and activity assumptions made in our calculation model should be validated by a third party and/or by the park management organizations e.g. through a workshop and should be regularly updated. We also recommend a sensitivity analysis of minimum and maximum amounts for different scenarios to be included in the calculation model. Furthermore the calculation model is generally applicable and can also be used and adapted to estimate the budget requirements of park management organizations on Curaçao and St. Maarten, and to calculate the appropriate level of the trust fund capital needed to ensure financial sustainability for nature management for the five participating islands