The city is a complex product that combines physical resources as well as cultural, historical, social, and economic aspects that influence the formation of its identity. In this way, the identity of a city is its DNA: a distinct, inherited combination of assets, history, characteristics, and culture that defines it internally and externally and has the power to unify people and place. Because identity is the foundation upon which a city's image is created, it is vital to consider how cities build and develop their identity. The city of Matosinhos will be the object of study, highlighting the city's unique characteristics that define its cultural identity. The deep connection to the sea remains the most important feature that characterises Matosinhos' identity. It is possible to note this relationship in several aspects since Matosinhos has one of the best port infrastructures in the country (the port of Leixões), a gastronomy rich in sea flavours (a pole of tourist attraction), a rich heritage with many monuments and sculptures dedicated to the sea, as well as important traditions and celebrations that contribute to preserving the spirit of its community. This relationship is also evident in the numerous economic activities that rely on the sea, as well as the hours of relaxation enjoyed by locals and tourists who visit the beaches and the sea to take advantage of this Matosinhos special feature. In the same way that the sea contributes to define the identity of Matosinhos, it also reveals how Matosinhos affirms its position for the development of a sustainable blue economy.