In the process of urbanization, protection of ecosystems and ensuring the continuity of the services they provide are very important in terms of the functionality of life support systems. Otherwise, degradation in ecosystems can have negative consequences for different dimensions, such as biodiversity decline, over-consumption of resources and climate change. In this context, as a result of urbanization, the loss of surface water drainage areas, the interruption of the continuity of green corridors and the increase in the size of impermeable surfaces cause problems in terms of sustainable development. Therefore, the attempts to ensure urban spatial development in harmony with natural areas in coastal areas are one of the most important issues of the planning agenda. The aim of the study is to reveal the relationship between the urban development pattern and the natural areas in the context of sustainable urban development, in the case of Mersin a coastal city in southern of Turkey. For this purpose, an interdisciplinary approach by using geographic information systems and remote sensing has been applied to understand the urban spatial patterns of Mersin. A multi-temporal change by using a series of satellite images for the three periods of 1987-2000-2015 have been analyzed. Threshold values was employed to detect built-up land and non-built-up land on the images. The results revealed that Mersin has spatially grown more than 6 times since 1980. The spatial growth is observed to increase by 80 % between 1987 and 2000 and by 60 % between 2000 and 2015. Under these circumstances, the development in Mersin has resulted in critical problems about decreasing of natural area in size, disconnecting of green network and degradation of coastal ecosystem. The results of the paper highlight the importance of determining the measurable variables for analyzing problems of urban forms for the future development strategies of cities.