Coastal zones have experienced rapid urban growth over the last 50 years and this is expected to continue. The most important reasons for rapid land-use changes are related to real estate pressure and the construction of new urban infrastructures. Coastal systems support a wide variety of social, economic and natural services and are directly affected by multiple human activities. The downside of urban increase is reflected in the change of land-use cover, and land-cover from open areas to built-up areas, especially within the metropolitan cities on the coast. The aim of the paper is to evaluate the relationship between the decrease of large green areas in coastal zones and the efficiency of planning and regulation of those areas. For this purpose, we are presenting a comparison between two case-studies from different countries: Boa Viagem Beach in Recife (Brazil) and Rocha Beach in Portimão (Portugal). These two areas have similar socio-environmental problems. The method relies on two sources: literature review (national regulation and policy documents) and 37 semi-structured interviews with stakeholders/agents responsible for urban development of the two areas of study. The interview questionnaire comprised topics such as the national planning legal framework, the process of urban growth, the impact of densification and the problems related to the lack of green areas in the coastal zones. A 3D GIS model complements the geospatial references of the research, showing the localization of green areas and their decrease over time. The comparison on different aspects of development in the two countries shows that the rules tend to be more efficient in Portugal than in Brazil. However, in both countries, it is felt that more efficient legal instruments and enforcement action is necessary to lead developers to comply with the rules. The use of semi-structured interviews proved to be very effective for comparative analysis on national policies. The paper presents a cross-national perspective with different stakeholders' points of view on the issue of the scarcity of green areas in coastal zones, which is intended to provide helpful information to planners, scholars and administration officers.