Nowadays, conceptual breakwater layout design mostly relies on experience and expert judgement, making it complicated to demonstrate that an economic optimum has been reached. This stresses the need to develop a tool that is able to establish the economically most attractive breakwater layout for a certain set of requirements and site-specific data. This study provides a proof of concept for a generative breakwater layout design tool, applicable to port projects all around the world. This is accomplished by investigating the most suitable optimisation method, by setting up a universally applicable methodology for the determination of the economic optimum and by establishing a robust and flexible model set-up. By validating it against a real case, the parametric model consistently comes up with breakwater layouts having cost estimates that are located within the desired accuracy range for the conceptual design phase. In addition, the parametric model is flexible, as it is able to efficiently deal with changes in design requirements and future port developments, therewith living up to modern design standards. In this way, client expectations are more likely to be met, leading to a spiral of increasing trust between the involved parties in an early design stage.